Self-flux growth method of high-quality CeAuSb2 single crystal

Abstract

The invention discloses a self-flux growth method of a high-quality CeAuSb2 single crystal, which effectively overcomes the problems of easy oxidation, poor quality of the single crystal, many defects, limited size of the single crystal and the like in the process of preparing the CeAuSb2 single crystal in the prior art by optimizing the stoichiometric proportion of raw materials and the growth process flow. And stable growth of a high-quality and large-size single crystal sample is realized. The method disclosed by the invention not only has important scientific research value, but also provides a solid technical basis for further expansion of the CeAuSb2 single crystal in practical application.

Description

Technical Field

[0001] This invention relates to the field of crystal growth technology for magnetic materials, and more particularly to a self-fluxed flux growth method for high-quality CeAuSb2 single crystals. Background Technology

[0002] In condensed matter physics, exploring the microscopic motion mechanisms of electrons in solids is one of the core research directions. The Coulomb interaction between electrons is a key factor influencing their microscopic behavior. When the strength of the Coulomb interaction significantly increases, the traditional theoretical framework based on the single-electron approximation no longer applies. At this point, the cooperative motion between electrons becomes exceptionally complex, exhibiting a rich array of exotic quantum phenomena under low-temperature conditions, forming the research field of strongly correlated electron systems. The study of the microscopic behavior of strongly correlated electrons has become a cutting-edge topic in condensed matter physics. In strongly correlated electron materials, degrees of freedom such as charge, spin, and orbital properties are coupled together under the drive of electron-electron interactions, generating various ordered electronic phases. These ordered phases are extremely similar on the energy scale, thus exhibiting highly sensitive response characteristics to external control parameters such as temperature, pressure, and magnetic fields. These ordered phases and their quantum competition and cooperative effects under regulation can not only trigger nontrivial physical phenomena such as topological phase transitions and metal-insulator transitions, but also show enormous application potential in cutting-edge technologies such as quantum information storage and high-temperature superconductivity. Therefore, in-depth research on strongly correlated electron systems can not only provide important theoretical support for understanding the fundamental laws of quantum many-body systems, but also provide key guidance for related experimental research, which has extremely important scientific significance and application value.

[0003] Heavy fermion systems are a typical class of strongly correlated electron systems. In their compounds, some electrons form quasiparticles under the combined influence of freely moving conduction band electrons and the spin field of the background lattice. These quasiparticles exhibit complex many-body interactions, giving rise to a wealth of quantum phenomena and providing a significant impetus for cutting-edge research and innovative applications in condensed matter physics. Taking heavy fermion superconductors as an example, these compounds can enter the superconducting state under externally controlled conditions such as low temperature or high pressure, exhibiting lossless electrical transport behavior in macroscopic quantum states. This characteristic not only provides a physical platform for developing next-generation low-energy quantum devices but also shows great application potential in energy and information fields such as lossless power transmission in power grids and high-field magnetic resonance imaging. Furthermore, the f electrons in heavy fermion compounds possess both localized and itinerant properties. Under low-temperature conditions, the interaction between itinerant f electrons and conduction electrons (i.e., the Kondo effect) leads to magnetic moment shielding. However, in some materials, this magnetic moment shielding competes with long-range magnetic order (such as antiferromagnetic or ferromagnetic order), resulting in complex magnetic phase diagrams. Therefore, heavy fermionic compounds have become an ideal platform for studying the relationship between strongly correlated physics and magnetic order. Notably, some heavy fermionic materials deviate from the description of traditional Fermi liquid theory at low temperatures, exhibiting anomalous transport and thermodynamic properties, such as singular magnetoresistance and high thermoelectric effects. These properties provide new insights for developing low-power electronic devices and quantum sensors. Furthermore, quantum entangled states in non-Fermi liquids can be used to construct stable qubits that are effectively resistant to environmental interference, thereby advancing the development of topological quantum computing.

[0004] In conclusion, research on heavy fermion compounds not only helps solve fundamental scientific problems in condensed matter physics and promotes innovative breakthroughs in quantum materials, but may also provide key material support for future technological revolutions, and has extremely important value for the development of basic science and applied technology.

[0005] CeAuSb₂ is a magnetic heavy fermion material of significant research value. With a stoichiometric ratio of 1:1:2, it exhibits a remarkable antiferromagnetic transition. The antiferromagnetic transition temperature (T0) of this compound is... N The antiferromagnetic transition temperature T is closely related to the occupancy of gold (Au) atoms in the crystal structure. NThe temperature distribution is roughly between 4.5 K and 6.8 K, with variations primarily influenced by Au atom occupancy. CeAuSb₂ crystals possess a tetragonal structure of the ZrCuSi₂ type, space group P⁴ / nmm (No. 129). Structurally, CeAuSb₂ can be considered a compound formed by inserting a layer of Au atoms into the parent CeSb₂ structure. Its relatively large c / a ratio (c / a ≈ 2.345) endows CeAuSb₂ with quasi-two-dimensional characteristics. Naturally grown CeAuSb₂ crystals exhibit a silvery-white lamellar morphology, good chemical stability, are not easily oxidized, and readily dissociate along the c-axis. Electrical transport and magnetic measurements show that CeAuSb₂ exhibits significant anisotropic behavior, closely related to its crystal structure and reflecting its quasi-two-dimensional electronic properties. CeAuSb2 possesses a large specific heat coefficient (approximately 90 mJ / mol·K²), indicating a strong correlation effect leading to electron effective mass renormalization, a key characteristic of heavy fermion materials. Further magnetic studies (HT phase diagram) reveal complex magnetic phase transition behavior in CeAuSb2 at low temperatures. In addition to the two known antiferromagnetic phases and one paramagnetic phase, intermediate phases with different magnetic moment alignment modes were observed, suggesting potential magnetic structure reconstruction under external field manipulation. Furthermore, under a certain magnetic field, CeAuSb2 may exhibit quantum critical behavior, making it an ideal platform for studying the interactions between quantum phase transitions, magnetic ordering, and correlation effects. Notably, the antiferromagnetic transition temperature of CeAuSb2 is closely related to the occupancy of Au atoms. The introduction of Au site defects significantly lowers the antiferromagnetic phase transition temperature and reduces crystal mass, hindering further research.

[0006] Therefore, increasing the occupancy rate of Au atoms at crystallographic lattice sites has become a key challenge in material preparation. Optimizing crystal growth process parameters (such as melt stoichiometry and temperature gradient) can effectively improve crystal quality and reduce defect concentration, which is crucial for obtaining high-quality single-crystal samples with well-defined magnetic phase boundaries. Improving the preparation techniques for such materials not only contributes to a deeper understanding of the control mechanisms of magnetic order and quantum critical behavior in heavy fermion systems, but also lays an important material foundation for developing novel spintronic devices and quantum computing architectures based on controllable magnetic phase transitions. Summary of the Invention

[0007] This invention aims to solve the problems of easy oxidation, poor single crystal quality, many defects, and limited single crystal size encountered in the preparation of CeAuSb2 single crystals in the existing technology, and to provide a self-generated flux growth method for high-quality CeAuSb2 single crystals.

[0008] To achieve the above-mentioned technical objectives, the technical solution provided by this invention is as follows: A self-fluxed flux growth method for high-quality CeAuSb2 single crystals, characterized by comprising the following steps: S1: The ingredients are prepared in a glove box filled with inert gas, including high-purity Ce rod raw materials, high-purity Au column raw materials, high-purity Sb particle raw materials, and quartz wool. S2: After pre-treating the alumina crucible, quartz tube, quartz plug, and manual baffle valve, place them into the glove box in S1; S3: Feeding and sealing of quartz tube; S4: Place the quartz tube packaged in S3 into a box furnace, set up a heating and cooling curve, heat from room temperature to 1050℃ at a rate of 50℃ / h, hold at 1050℃ for 24 h, then cool down to 700℃ at a rate of 1.56℃ / h, invert the quartz tube and centrifuge to remove excess raw materials and flux, and obtain high-quality CeAuSb2 single crystal after cooling.

[0009] Furthermore, in S1, the high-purity Ce rod raw material, high-purity Au column raw material, and high-purity Sb particle raw material are mixed in an atomic ratio of 1:4 to 6:21.

[0010] Specifically, using the above-mentioned ingredients can minimize the generation of defects in single crystals and significantly improve the Au occupancy rate.

[0011] Furthermore, in S1, the inert gas includes high-purity argon or high-purity nitrogen with a purity of ≥99.99%.

[0012] Specifically, high-purity argon is preferred, and the purpose of filling the glove box with high-purity argon or nitrogen is to avoid introducing additional impurities.

[0013] Furthermore, in S1, the purity of the high-purity Ce rod raw material is ≥99.99%, the purity of the high-purity Au column raw material is ≥99.999%, and the purity of the high-purity Sb particle raw material is ≥99.999%.

[0014] Furthermore, in S1, the high-purity Ce rod raw material also needs to undergo surface polishing treatment, using fine sandpaper with a mesh size of ≥1200.

[0015] Specifically, the polishing process involves first wiping the grayish-white oxide off the surface of the Ce rod with lint-free paper inside the glove box, then polishing the Ce rod with a file and fine sandpaper until the surface reveals a metallic luster, and finally wiping away any surface debris with lint-free paper before use.

[0016] In this method, the outer layer of Ce raw material is polished to remove impurities, and the reaction is strictly controlled under an inert atmosphere in a glove box to ensure that no additional impurities are introduced into the reaction, thus achieving uniform and high-quality crystal growth.

[0017] Furthermore, in S2, the pretreatment step includes first vacuum drying the alumina crucible, quartz tube, quartz stopper, and manual baffle valve, and then cleaning, drying, and storing the alumina crucible, quartz tube, and quartz stopper.

[0018] Furthermore, the cleaning method involves immersing the alumina crucible, quartz tube, and quartz stopper in anhydrous ethanol, ultrasonically cleaning for 15-20 minutes, and drying at 150℃-200℃.

[0019] Specifically, the above-mentioned cleaning and drying methods can effectively remove surface deposits and reduce the impact of impurities on the growth process.

[0020] Furthermore, in S3, the feeding and packaging of the quartz tube includes the following steps: S31: Place the high-purity Ce rod raw material and high-purity Au column raw material from S1 into the bottom of the alumina crucible, and then add the high-purity Sb particle raw material. Specifically, Ce and Au raw materials are first placed at the bottom of the crucible, followed by Sb raw material. This order can effectively shorten the atomic diffusion time during the growth process and improve the yield.

[0021] S32: Place the alumina crucible treated in S31 into a quartz tube, insert a piece of quartz wool on top of the alumina crucible, and place a quartz plug on top of the quartz wool. Connect the manual baffle valve in the inert gas environment inside the glove box and tighten the seal before taking out the quartz tube. S33: Vacuum the quartz tube treated in S32. The required vacuum should be better than 2*10. -3 Pa; S34: The quartz tube treated in S33 is sealed using an oxyhydrogen welding machine so that the molten part of the quartz tube is completely bonded to the quartz plug.

[0022] Specifically, in this solution, the quartz tube is customized according to the size of the centrifuge, with an inner diameter of 14mm, an outer diameter of 17mm, a length of approximately 25cm, and a maximum designed operating temperature of 1150℃.

[0023] The reason why the quartz tube melts completely adheres to the quartz plug is that there is a pressure difference between the inside and outside of the quartz tube melts. In addition, there is a significant "diameter reduction" phenomenon at the top of the quartz plug.

[0024] Furthermore, in S33, the vacuuming process involves first using a mechanical pump to evacuate the vacuum to a level better than 5*10. -1 Pa, then the molecular pump is turned on to evacuate the vacuum inside the quartz tube to 1*10 Pa. -3 The order of magnitude is Pa.

[0025] Specifically, the combination of mechanical pumps and molecular pumps is an effective and common vacuum extraction method, which has the advantage of efficiently obtaining a vacuum.

[0026] Furthermore, in S34, the specific method includes: first, turning on the oxyhydrogen welding machine, and after the sprayed mixed gas stabilizes, igniting it with a lighter, then immediately closing the quartz tube baffle valve and quickly removing the quartz tube; using the oxyhydrogen welding machine to seal the quartz tube, so that the quartz tube melts at the point of contact with the flame, and completely adheres to the quartz plug due to the pressure difference between the inside and outside; first sealing one ring around the middle of the quartz plug, and then sealing one ring around the top of the quartz plug to maintain the vacuum inside the quartz tube.

[0027] In this solution, the oxyhydrogen welding machine needs to be ignited, and the quartz tube needs to be sealed immediately after removal; otherwise, the vacuum inside the quartz tube will not reach 1*10. -3 The pressure difference is on the order of Pa, which reduces the pressure difference between the inside and outside, thus increasing the difficulty of sealing.

[0028] Another aspect of the present invention provides a high-quality CeAuSb2 single crystal, wherein the CeAuSb2 single crystal is in the form of a bright silver flake on the order of centimeters.

[0029] Specifically, in S4, in addition to setting the heating and cooling curves of the quartz tube, two heat preservation curves also need to be set. The first curve is to ensure that the raw materials are mixed evenly, while the heat preservation curve that drops to the lowest temperature is convenient for centrifugation at any time. Since the temperature of the quartz tube is very high after centrifugation, it should be waited for the temperature of the quartz tube to drop before breaking the quartz tube to avoid the single crystal being oxidized at high temperature, which would affect the quality of the single crystal.

[0030] The present invention has the following beneficial effects: 1. Reduce oxidation risk and improve growth stability In existing technologies, rapid heating and cooling rates easily lead to thermal stress accumulation in the quartz tube, which can cause the tube to crack and expose the reactive raw material to air for oxidation. This invention effectively suppresses thermal stress accumulation in the quartz tube by precisely controlling the heating and cooling rates, significantly reducing the risk of quartz tube cracking. This improvement not only avoids oxidation of the raw material during growth but also prevents oxidation and deterioration of the single-crystal sample caused by quartz tube cracking during centrifugation, thereby significantly improving the success rate of single-crystal growth and solving the problem of easy oxidation of the single-crystal surface in existing technologies.

[0031] 2. Significantly improves single crystal quality Existing techniques for preparing CeAuSb2 single crystals suffer from low residual resistivity and numerous defects, making it difficult to meet the demands of high-quality research. This invention, through precise control of the chemical composition of raw materials and optimization of crystal growth conditions, effectively suppresses the formation of defects in the single crystal material and significantly increases the occupancy rate of Au atoms in the crystal lattice. This provides a more ideal sample for subsequent related research and solves the problems of poor single crystal quality and numerous defects in existing techniques.

[0032] 3. Breaking through the limitations of single crystal size In existing technologies, due to the rapid cooling rate of eutectic melts, single-crystal samples tend to grow in a stepped manner along the c-axis, forming thick, bulky crystals that are difficult to dissociate, hindering subsequent measurements and characterization. This invention, through an improved growth process, achieves large-scale growth of CeAuSb2 quasi-two-dimensional single crystals, resulting in a centimeter-scale lamellar crystal morphology. This improvement overcomes the limitations of crystal morphology and size in existing technologies, greatly facilitating subsequent research and characterization while reducing the complexity of experimental operations.

[0033] 4. Improve product purity In existing technologies, the introduction of impurities is a significant cause of insufficient single-crystal purity. This invention effectively avoids the introduction of impurities by storing the alumina crucible, quartz tube, and quartz stopper required during the preparation process in a constant-temperature drying oven and subjecting them to rigorous cleaning and drying. This measure significantly improves the purity of the product and solves the problem of insufficient single-crystal purity caused by impurities in existing technologies.

[0034] 5. Optimize sealing effect In existing technologies, inadequate sealing is a major cause of raw material oxidation and crystal growth failure. This invention employs a sealing method using an oxyhydrogen flame, rotating the quartz plug once in the middle and then once at the top. This operation not only maintains a good vacuum environment inside the quartz tube but also causes the quartz tube to retract significantly, facilitating the subsequent removal of the upper portion. By optimizing the sealing process, the problems of raw material oxidation and low single crystal quality caused by inadequate sealing are effectively avoided.

[0035] 6. Strictly control the purity of raw materials In existing technologies, the introduction of impurities is a significant cause of poor single crystal quality and even growth failure. This invention addresses this issue by rigorously controlling impurity introduction through measures such as polishing the outer Ce material to remove impurities, conducting sealed operations under an inert atmosphere within a glove box, and employing a self-fluxing method using Sb as a flux. These improvements ensure the purity of the reaction process, achieving uniform, high-quality sample growth and resolving the problem of poor crystal quality caused by impurity introduction in existing technologies. Attached Figure Description

[0036] Figure 1These are the energy spectrum and sample image of the CeAuSb2 single crystal sample prepared in Example 1; Figure 2 This is the resistivity curve within the ab plane of the CeAuSb2 single crystal sample prepared in Example 1; Figure 3 These are the energy spectrum and sample image of the CeAuSb2 single crystal sample prepared in Example 2; Figure 4 This is the resistivity curve within the ab plane of the CeAuSb2 single crystal sample prepared in Example 2; Figure 5 These are the energy spectrum and sample image of the CeAuSb2 single crystal sample prepared in Example 3; Figure 6 This is the resistivity curve within the ab plane of the CeAuSb2 single crystal sample prepared in Example 3; Figure 7 The energy spectrum and sample image of the CeAuSb2 single crystal sample prepared in Comparative Example 1 are shown. Figure 8 The resistivity curve of the CeAuSb2 single crystal sample prepared in Comparative Example 1 is shown in the ab plane. Figure 9 This is the X-ray diffraction pattern of the CeAuSb2 single crystal sample prepared by the method in Example 1; Figure 10 These are Laue diffraction spots of the CeAuSb2 single crystal sample prepared by the method in Example 1; Figure 11 These are angle-resolved photoelectron spectroscopy (ARPES) data of the CeAuSb2 single crystal sample prepared by the method in Example 1; (a) shows the crystal structure of CeAuSb2, (b) shows a schematic diagram of the Brillouin zone of CeAuSb2, and (c) shows... k z The electronic structure in the direction, (d)-(i) are the Fermi surface topology and band structure in the high symmetry direction of the Brillouin zone. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Example 1 A novel self-fluxed flux growth method for high-quality CeAuSb2 single crystals includes the following steps: S1. Prepare Ce rod raw materials (99.99% purity), Au column raw materials (99.999% purity), Sb particle raw materials (99.999% purity), and quartz wool in a glove box filled with inert gas. Remove the alumina crucible, quartz tube, quartz stopper, and manual baffle valve from the vacuum drying oven. The quartz tube has an inner diameter of 14 mm, an outer diameter of 17 mm, and a length of approximately 25 cm. The inert gas is high-purity argon or high-purity nitrogen with a purity ≥ 99.99%.

[0040] S2. Surface polishing of the Ce rod raw material: First, wipe off the grayish-white oxide on the surface of the Ce rod with lint-free paper inside a glove box. Then, polish the Ce rod with a file and 1200-grit sandpaper until the surface shows a metallic luster. Finally, wipe off surface debris with lint-free paper. In an atmospheric environment, use an ultrasonic cleaner to clean the inner and outer walls of the alumina crucible, quartz tube, and quartz stopper immersed in anhydrous ethanol for 15-20 minutes. After removal and wiping, dry them on a heating table at 150℃-200℃.

[0041] S3. Transfer the manual baffle valve from step S1, along with the alumina crucible, quartz tube, and quartz plug processed in step S2, into the glove box.

[0042] S4. In the glove box, mix Ce raw material: Au raw material: Sb raw material in an atomic ratio of 1:6:21. First, put Ce raw material and Au raw material into the bottom of the alumina crucible, and then use excess Sb as a flux in the alumina crucible.

[0043] S5. After the crucible processed in step S4 is placed into the quartz tube, a piece of quartz wool is inserted on top of the crucible to leave space for the subsequent centrifugation step, and a quartz stopper is placed on top of the quartz wool. After connecting the manual baffle valve and tightening the seal in the inert gas environment inside the glove box, the quartz tube is removed.

[0044] S6. Connect the quartz tube processed in step S5 to the vacuum pump assembly for vacuuming. Use a mechanical pump + molecular pump to create a vacuum. First, use the mechanical pump to evacuate the vacuum to a level better than 5*10. -1 Pa, then the molecular pump is turned on to evacuate the vacuum inside the quartz tube to 1*10 Pa. -3 The magnitude is on the order of Pa, and the final vacuum should be better than 2*10. -3 Pa; S7. Seal the quartz tube treated in step S6 using an oxyhydrogen welding machine. First, turn on the oxyhydrogen welding machine, and after the sprayed mixed gas stabilizes, ignite it with a lighter. Then, immediately close the quartz tube baffle valve and quickly remove the quartz tube. Using the oxyhydrogen welding machine to seal the quartz tube causes the quartz tube to melt at the point of contact with the flame, and due to the pressure difference between the inside and outside, it completely adheres to the quartz plug, achieving a sealing effect. Afterward, use a flame to heat the upper part of the quartz plug, causing it to produce a noticeable "diameter reduction" phenomenon, making it easier to remove the upper part of the quartz tube later. S8. Separate the quartz tube processed in step S7 from the manual baffle valve, knock off the excess quartz tube at the top, place a large alumina crucible in the box furnace, and vertically place the quartz tube into the large crucible. S9. Set up a heating and cooling curve. Heat the temperature from room temperature to 1050℃ at a rate of 50℃ / h, hold it at 1050℃ for 24h, and then cool it down to 700℃ at a rate of 1.56℃ / h. Turn the quartz tube over and centrifuge it. Set the centrifuge speed to 2000r / min and the running time to 1.5min. Remove excess raw materials and flux. S10. Take out the quartz tube processed in step S9. After cooling, break the quartz tube and the alumina crucible. Centimeter-sized bright silver flake-shaped CeAuSb2 single crystals are generated at the bottom of the alumina crucible, while excess raw materials and flux are concentrated at the top of the crucible.

[0045] Figure 1 This document presents the elemental composition, micro-area composition, energy dispersive spectroscopy (EDS) spectrum, and physical image of the CeAuSb2 single crystal sample prepared in Example 1. EDS analysis results indicate that the CeAuSb2 single crystal sample grown using the process in Example 1 is mainly composed of Ce, Au, and Sb, with the oxygen content below the instrument detection limit. Notably, the sample maintains an extremely low oxygen content even after long-term exposure to the atmosphere, confirming the material's stability in atmospheric conditions. Semi-quantitative elemental analysis shows that the Ce:Au:Sb atomic percentages (25.50%:25.54%:48.96%) are highly consistent with the theoretical stoichiometry, confirming the sample's high crystallinity and low defect concentration. Macroscopic morphological observation reveals that the obtained single crystal exhibits a typical layered structure, consistent with the characteristics of the quasi-two-dimensional tetragonal crystal structure of CeAuSb2. The crystal size reaches the centimeter scale, and the surface displays a uniform silvery-white metallic luster. Furthermore, clear step-like growth patterns can be observed on the crystal surface. This morphological feature further confirms that the crystal growth process follows a good step-like growth mechanism, providing intuitive evidence for the excellent crystallization quality of the material.

[0046] Figure 2The resistivity-temperature curves of the CeAuSb2 single crystal sample prepared in Example 1 within the ab crystal plane are shown. In the high-temperature range (T > 50 K), the resistivity decreases approximately linearly with decreasing temperature, a behavior consistent with the electrical transport properties of conventional metals. When the temperature drops to approximately 50 K, the system begins to deviate from a strictly linear relationship. With further decreasing temperature, a significant resistivity inflection point is observed near 6.6 K, corresponding to the establishment of antiferromagnetic order in the material, marking the magnetic phase transition process. Entering the low-temperature range (T < 6.6 K), the resistivity exhibits a significant quadratic dependence on temperature (ρ ∝ T). 2 This scaling behavior confirms that the system conforms to the fundamental characteristics of Fermi liquid theory in a magnetically ordered state. A more intuitive parameter for evaluating the quality of single-crystal materials is the RRR value, defined as the ratio of the material's room-temperature resistivity to its residual resistivity (resistivity near absolute zero, which is the resistivity at 2 K in this invention). It is used to characterize the purity and crystal integrity of the material; the higher the RRR value, the higher the quality of the material and the fewer crystal defects. The CeAuSb2 single-crystal sample prepared by the method in this embodiment has an RRR value of approximately 6.9, indicating high single-crystal quality and few defects.

[0047] Example 2 S1. Prepare Ce rod raw materials with a purity of 99.99%, Au column raw materials with a purity of 99.999%, Sb particle raw materials with a purity of 99.999%, and quartz wool in a glove box filled with inert gas. Take out the alumina crucible, quartz tube, quartz plug, and manual baffle valve from the vacuum drying oven.

[0048] S2. The Ce rod raw material is surface polished, and the alumina crucible, quartz tube and quartz plug are cleaned and dried.

[0049] S3. Transfer the manual baffle valve from step S1, along with the alumina crucible, quartz tube, and quartz plug processed in step S2, into the glove box.

[0050] S4. In the glove box, mix Ce raw material: Au raw material: Sb raw material in an atomic ratio of 1:5:21. First, put Ce raw material and Au raw material into the bottom of the alumina crucible, and then use excess Sb as a flux in the alumina crucible.

[0051] S5. After the crucible processed in step S4 is placed into the quartz tube, a piece of quartz wool is inserted on top of the crucible to leave space for the subsequent centrifugation step, and a quartz stopper is placed on top of the quartz wool. After connecting the manual baffle valve and tightening the seal in the inert gas environment inside the glove box, the quartz tube is removed.

[0052] S6. Connect the quartz tube processed in step S5 to the vacuum pump assembly for vacuuming. The final vacuum should be better than 2*10. -3 Pa.

[0053] S7. Seal the quartz tube treated in step S6 using an oxyhydrogen welding machine, so that the quartz tube melts at the point of contact with the flame, and completely adheres to the quartz plug due to the pressure difference between the inside and outside, thus achieving a sealing effect. S8. Separate the quartz tube processed in step S7 from the manual baffle valve, knock off the excess quartz tube at the top, place a large alumina crucible in the box furnace, and vertically place the quartz tube into the large crucible.

[0054] S9. Set up a heating and cooling curve, raise the temperature from room temperature to 1050℃ at a rate of 50℃ / h, hold at 1050℃ for 24h, then lower the temperature to 700℃ at a rate of 1.56℃ / h, invert the quartz tube and centrifuge to remove excess raw materials and flux.

[0055] S10. Take out the quartz tube processed in step S9. After cooling, break the quartz tube and the alumina crucible. Centimeter-sized CeAuSb2 single crystals are generated at the bottom of the alumina crucible, while excess raw materials and flux are concentrated at the top of the crucible.

[0056] Figure 3 This document presents the elemental composition, micro-area composition, energy dispersive spectroscopy (EDS) spectrum, and physical image of the CeAuSb2 single crystal sample prepared in Example 2. EDS analysis results indicate that the CeAuSb2 single crystal sample grown using the process in Example 2 is mainly composed of Ce, Au, and Sb. Semi-quantitative elemental analysis shows that the atomic percentages of Ce:Au:Sb are (25.58%:25.75%:48.67%), indicating high crystal quality and few defects in the single crystal sample. Macroscopic morphological observation shows that the obtained single crystal exhibits a lamellar morphology, with crystal sizes on the order of centimeters. The surface displays a silvery-white metallic luster, and step-like growth patterns can also be observed on the crystal surface.

[0057] Figure 4 The resistivity-temperature curves of the CeAuSb2 single crystal sample prepared in Example 2 within the ab crystal plane are shown. In the high-temperature range (T > 50 K), the resistivity curve also shows a linear decreasing trend with decreasing temperature. When the temperature drops to about 50 K, the system begins to deviate from a strictly linear relationship. With further decreasing temperature, a significant resistivity inflection point is observed near 6.6 K. This feature corresponds to the establishment of antiferromagnetic order in the material, marking the magnetic phase transition process of the system. After entering the low-temperature range (T < 6.6 K), the resistivity shows a significant quadratic dependence on temperature (ρ ∝ T). 2This scaling behavior confirms that the system conforms to the fundamental characteristics of Fermi liquid theory in a magnetically ordered state. The single crystal sample obtained by the method in this embodiment has an RRR value of approximately 6.2, indicating high single crystal quality and few crystal defects.

[0058] Example 3 S1. Prepare Ce rod raw materials with a purity of 99.99%, Au column raw materials with a purity of 99.999%, Sb particle raw materials with a purity of 99.999%, and quartz wool in a glove box filled with inert gas. Take out the alumina crucible, quartz tube, quartz plug, and manual baffle valve from the vacuum drying oven.

[0059] S2. The Ce rod raw material is surface polished, and the alumina crucible, quartz tube and quartz plug are cleaned and dried.

[0060] S3. Transfer the manual baffle valve from step S1, along with the alumina crucible, quartz tube, and quartz plug processed in step S2, into the glove box.

[0061] S4. In the glove box, mix Ce raw material: Au raw material: Sb raw material in an atomic ratio of 1:4:21. First, put Ce raw material and Au raw material into the bottom of the alumina crucible, and then use excess Sb as a flux in the alumina crucible.

[0062] S5. After the crucible processed in step S4 is placed into the quartz tube, a piece of quartz wool is inserted on top of the crucible to leave space for the subsequent centrifugation step, and a quartz stopper is placed on top of the quartz wool. After connecting the manual baffle valve and tightening the seal in the inert gas environment inside the glove box, the quartz tube is removed.

[0063] S6. Connect the quartz tube processed in step S5 to the vacuum pump assembly for vacuuming. The final vacuum should be better than 2*10. -3 Pa.

[0064] S7. Seal the quartz tube treated in step S6 using an oxyhydrogen welding machine, so that the quartz tube melts at the point of contact with the flame, and completely adheres to the quartz plug due to the pressure difference between the inside and outside, thus achieving a sealing effect. S8. Separate the quartz tube processed in step S7 from the manual baffle valve, knock off the excess quartz tube at the top, place a large alumina crucible in the box furnace, and vertically place the quartz tube into the large crucible. S9. Set up a heating and cooling curve, raise the temperature from room temperature to 1050℃ at a rate of 50℃ / h, hold at 1050℃ for 24h, and then lower the temperature to 700℃ at a rate of 1.56℃ / h. Turn the quartz tube over and centrifuge to remove excess raw materials and flux. S10. Take out the quartz tube processed in step S9. After cooling, break the quartz tube and the alumina crucible. Near-centimeter-sized CeAuSb2 single crystals are generated at the bottom of the alumina crucible, while the excess raw materials and flux are concentrated at the top of the crucible.

[0065] Figure 5 This document presents the elemental composition, micro-area composition, energy dispersive spectroscopy (EDS) spectrum, and physical image of the CeAuSb2 single crystal sample prepared in Example 3. EDS analysis results indicate that the CeAuSb2 single crystal sample grown using the process in Example 3 is mainly composed of Ce, Au, and Sb. Semi-quantitative elemental analysis shows that the atomic percentages of Ce:Au:Sb are (25.39%:25.12%:49.49%), indicating high sample quality and few defects. Macroscopic morphological observation reveals that the obtained single crystal exhibits a lamellar crystal morphology, with an overall size approaching the centimeter scale. The surface displays a silvery-white metallic luster, and distinct step-like growth patterns can be observed on the crystal surface.

[0066] Figure 6 The resistivity-temperature curves of the CeAuSb2 single crystal sample prepared in Example 3 within the ab crystal plane are shown. In the high-temperature range, the resistivity curve also shows a linear decreasing trend with decreasing temperature. Below 50 K, the system begins to deviate from a strictly linear relationship. A significant resistivity inflection point is observed near 6.5 K, which corresponds to the establishment of antiferromagnetic order in the material, marking the magnetic phase transition process. Entering the low-temperature range (T < 6.5 K), the resistivity exhibits a significant square dependence on temperature (ρ ∝ T). 2 The single crystal sample obtained by the method in this embodiment has an RRR value of approximately 7.0, indicating that the single crystal has high quality and few crystal defects.

[0067] Comparative Example 1 S1. Prepare Ce rod raw materials with a purity of 99.99%, Au column raw materials with a purity of 99.999%, Sb particle raw materials with a purity of 99.999%, and quartz wool in a glove box filled with inert gas. Take out the alumina crucible, quartz tube, quartz plug, and manual baffle valve from the vacuum drying oven.

[0068] S2. The Ce rod raw material is surface polished, and the alumina crucible, quartz tube and quartz plug are cleaned and dried.

[0069] S3. Transfer the manual baffle valve from step S1, along with the alumina crucible, quartz tube, and quartz plug processed in step S2, into the glove box.

[0070] S4. In the glove box, mix Ce raw material: Au raw material: Sb raw material in an atomic ratio of 1:2:21. First, put Ce raw material and Au raw material into the bottom of the alumina crucible, and then use excess Sb as a flux in the alumina crucible.

[0071] S5. After the crucible processed in step S4 is placed into the quartz tube, a piece of quartz wool is inserted on top of the crucible to leave space for the subsequent centrifugation step, and a quartz plug is placed on top of the quartz wool. After connecting the manual baffle valve and tightening the seal in the inert gas environment inside the glove box, the quartz tube is removed.

[0072] S6. Connect the quartz tube processed in step S5 to the vacuum pump assembly for vacuuming. The final vacuum should be better than 2*10. -3 Pa.

[0073] S7. Seal the quartz tube treated in step S6 using an oxyhydrogen welding machine, so that the quartz tube melts at the point of contact with the flame, and completely adheres to the quartz plug due to the pressure difference between the inside and outside, thus achieving a sealing effect.

[0074] S8. Separate the quartz tube processed in step S7 from the manual baffle valve, knock off the excess quartz tube at the top, place a large alumina crucible in the box furnace, and vertically place the quartz tube into the large crucible.

[0075] S9. Set up a heating and cooling curve, raise the temperature from room temperature to 1050℃ at a rate of 100℃ / h, hold at 1050℃ for 24h, then lower the temperature to 700℃ at a rate of 2℃ / h, invert the quartz tube and centrifuge to remove excess raw materials and flux.

[0076] S10. Take out the quartz tube processed in step S9. After cooling, break the quartz tube and the alumina crucible. Millimeter-sized CeAuSb2 single crystals are generated at the bottom of the alumina crucible, while excess raw materials and flux are concentrated at the top of the crucible.

[0077] Figure 7 This document presents the elemental composition, micro-area composition, energy dispersive spectroscopy (EDS) spectrum, and physical images of CeAuSb2 single crystal samples prepared according to methods described in previous literature. EDS analysis results indicate that the CeAuSb2 single crystal sample grown using the process described in Comparative Example 1 is primarily composed of Ce, Au, and Sb. Semi-quantitative elemental analysis shows that the atomic percentages of Ce:Au:Sb are (25.26%:24.52%:50.22%), indicating a significant number of Au site defects in the sample. Macroscopic morphological observation reveals that the obtained single crystal exhibits a bulk crystal morphology, with an overall size on the order of millimeters, and some flux residue is present on the surface.

[0078] Figure 8The resistivity-temperature curves of the CeAuSb2 single crystal sample prepared using the method of Comparative Example 1 within the ab crystal plane are shown. In the high-temperature range, the resistivity curve shows a linear decreasing trend with decreasing temperature. Near 50 K, the curve slightly bulges, possibly related to Kondo's work. A significant resistivity inflection point is observed near 4.5 K, corresponding to the establishment of antiferromagnetic order in the material, indicating that the system has undergone a magnetic phase transition. Entering the low-temperature range (T < 4.5 K), the resistivity exhibits an approximately square-dependent relationship with temperature (ρ ∝ T). 2 Overall, the resistivity curves of the single-crystal samples in Comparative Example 1 and the Examples show significant differences in shape, and the antiferromagnetic transition temperature is significantly lower. The RRR value of the single-crystal sample obtained by the comparative example method is about 1.6, indicating that the single crystal quality is low, with many crystal defects, and the single crystal quality is significantly lower than that of the single-crystal sample obtained by the method of the Examples.

[0079] Figure 9 The X-ray diffraction pattern of the CeAuSb2 single crystal sample prepared by the method in Example 1 shows clear and sharp diffraction peaks. These diffraction peaks belong to the (0 0 l) crystal plane cluster, indicating that the natural growth plane of the single crystal corresponds to the (0 0 l) crystal plane cluster. No other impurity peaks were found, indicating that the single crystal has high quality and good crystallinity.

[0080] Figure 10 The image shows the Laue diffraction results of the CeAuSb2 single crystal sample prepared by the method in Example 1. The diffraction spots in the image are very clear and exhibit a typical tetragonal arrangement. After comparison with the theoretical pattern, it was found that the distribution of the spots conforms to the CeAuSb2 crystal structure, indicating that the single crystal has high quality.

[0081] Figure 11 Figure 1 shows the angle-resolved photoelectron spectroscopy (ARPES) data of the CeAuSb2 single-crystal sample prepared by the method in Example 1. This data was obtained using an ARPES device. The use of this device requires that the sample being measured has high quality and is a single crystal; otherwise, the obtained data will not show a significant dispersive signal. The single-crystal sample obtained by the self-fluxing method in Example 1 shows clear electronic structure features. Figure (a) shows the crystal structure of CeAuSb2, which can be considered as a quasi-two-dimensional layered compound consisting of a single Au atom layer inserted into the parent CeSb2. Figure (b) shows the Brillouin zones in the corresponding reciprocal space, with high-symmetry directions marked. Figure (c) shows... k zThe electronic structure of CeAuSb2 is shown in Figures (d)-(i), where 106 eV and 94 eV are used to probe the Γ-MX and ZAR planes in the Brillouin zone, respectively. Figures (d)-(i) show the Fermi surface topology and corresponding band dispersion of CeAuSb2. Overall, the electronic structure of CeAuSb2 exhibits quasi-two-dimensional characteristics, corresponding to its crystal structure. Furthermore, the clear, approximately rhomboid Fermi surface and the band structure near the Fermi surface indicate good single-crystal quality, meeting the requirements for detailed electronic structure and f-electronic property studies. This invention lays a solid foundation for subsequent research and possesses significant scientific value.

[0082] Table 1 shows a comparison of the performance of CeAuSb2 single crystal products prepared in Examples 1-3 and Comparative Example 1.

[0083] Table 1 shows the performance comparison of the CeAuSb2 single crystal products prepared in Examples 1-3 and Comparative Example 1. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0084] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A self-fluxed flux growth method for high-quality CeAuSb2 single crystals, characterized in that, Includes the following steps: S1: Prepare the ingredients in a glove box filled with inert gas. The ingredients include high-purity Ce rod raw material, high-purity Au column raw material, high-purity Sb particle raw material, and quartz wool. S2: After pre-treating the alumina crucible, quartz tube, quartz plug, and manual baffle valve, place them into the glove box in S1; S3: Feeding and sealing of quartz tube; S4: Place the quartz tube packaged in S3 into a box furnace, set up a heating and cooling curve, heat from room temperature to 1050℃ at a rate of 50℃ / h, hold at 1050℃ for 24 h, then cool down to 700℃ at a rate of 1.56℃ / h, invert the quartz tube and centrifuge to remove excess raw materials and flux, and obtain high-quality CeAuSb2 single crystal after cooling.

2. The self-fluxed flux growth method for high-quality CeAuSb2 single crystals according to claim 1, characterized in that, In S1, the high-purity Ce rod raw material, high-purity Au column raw material, and high-purity Sb particle raw material are mixed in an atomic ratio of 1:4 to 6:

21.

3. The self-flush flux growth method for high-quality CeAuSb2 single crystal according to claim 1, characterized in that, In S1, the inert gas includes high-purity argon or high-purity nitrogen with a purity of ≥99.99%.

4. The self-fluxed flux growth method for high-quality CeAuSb2 single crystal according to claim 1, characterized in that, In S1, the purity of the high-purity Ce rod raw material is ≥99.99%, the purity of the high-purity Au column raw material is ≥99.999%, and the purity of the high-purity Sb particle raw material is ≥99.999%.

5. The self-fluxed flux growth method for high-quality CeAuSb2 single crystals according to claim 1, characterized in that, In S1, the high-purity Ce rod raw material also needs to undergo surface polishing treatment, using fine sandpaper with a mesh size of ≥1200.

6. The self-fluxed flux growth method for high-quality CeAuSb2 single crystals according to claim 1, characterized in that, In S2, the pretreatment steps include first vacuum drying the alumina crucible, quartz tube, quartz stopper, and manual baffle valve, and then cleaning, drying, and storing the alumina crucible, quartz tube, and quartz stopper.

7. The self-flush flux growth method for high-quality CeAuSb2 single crystal according to claim 6, characterized in that, The cleaning method involves immersing the alumina crucible, quartz tube, and quartz stopper in anhydrous ethanol, ultrasonically cleaning for 15-20 minutes, and drying at 150℃-200℃.

8. The self-flush flux growth method for high-quality CeAuSb2 single crystal according to claim 1, characterized in that, In S3, the feeding and sealing of the quartz tube includes the following steps: S31: Place the high-purity Ce rod raw material and high-purity Au column raw material from S1 into the bottom of the alumina crucible, and then add the high-purity Sb particle raw material. S32: Place the alumina crucible treated in S31 into a quartz tube, insert a piece of quartz wool on top of the alumina crucible, and place a quartz plug on top of the quartz wool. Connect the manual baffle valve in the inert gas environment inside the glove box and tighten the seal before taking out the quartz tube. S33: Vacuum the quartz tube treated in S32. The required vacuum should be better than 2*10. -3 Pa; S34: The quartz tube treated in S33 is sealed using an oxyhydrogen welding machine so that the molten part of the quartz tube is completely bonded to the quartz plug.

9. The self-flush flux growth method for high-quality CeAuSb2 single crystal according to claim 8, characterized in that, In S33, the vacuuming process involves first using a mechanical pump to evacuate the vacuum to a level better than 5*10. -1 Pa, then the molecular pump is turned on to evacuate the quartz tube to 1*10 Pa. -3 The order of magnitude is Pa.

10. The self-flush flux growth method for high-quality CeAuSb2 single crystal according to claim 8, characterized in that, In S34, the specific method includes: first, turning on the oxyhydrogen welding machine, and after the sprayed mixed gas stabilizes, igniting it with a lighter, then immediately closing the quartz tube baffle valve and quickly removing the quartz tube; using the oxyhydrogen welding machine to seal the quartz tube, so that the quartz tube melts at the point of contact with the flame, and completely adheres to the quartz plug due to the pressure difference between the inside and outside; first sealing one ring around the middle of the quartz plug, and then sealing one ring around the top of the quartz plug to maintain the vacuum inside the quartz tube.

11. A high-quality CeAuSb2 single crystal grown using any one of the methods described in claims 1-10, characterized in that, The CeAuSb2 single crystals are in the form of bright silver flakes on the order of centimeters.

Images