Method for growing Kagome metal AV3Sb5 single crystal

Abstract

The invention relates to the technical field of crystal growth in the field of condensed physics and material science, in particular to a method for growing a Kagome metal AV3Sb5 single crystal. According to the method, a direct self-service solvent method is combined with a specific temperature control program, so that the effective growth of the Kagome metal single crystal is realized, and an important material basis is provided for deeply researching a quantum phenomenon in a Kagome crystal lattice; meanwhile, the possibility is provided for preparing low-energy-consumption electronic components, superconducting diodes, nano optical and photonics devices and other applications; according to the method, the quality and size of the single crystal are improved, the growth process is simplified, the repeatability and stability are enhanced, flexible regulation and control of Mn doping are realized, the application field is widened, and compared with the prior art, the method has remarkable advantages and beneficial effects.

Description

Technical Field

[0001] The present invention relates to the field of crystal growth technology in the field of condensed matter physics and material science, and in particular to a method for growing Kagome metal AV 3 Sb 5 Single crystal method. Background Art

[0002] The Kagome lattice, with its unique corner-sharing triangular structure, has become an ideal platform for studying many quantum phenomena. These quantum phenomena include but are not limited to frustrated magnetism, topological states, density waves, and unconventional superconductivity. They mainly originate from the intrinsic flat bands, Dirac cones, and van Hove singularities in the Brillouin zone, and are deeply dependent on the band filling. In recent years, a new class of Kagome metals AV 3 Sb 5 (where A represents alkali metal elements such as K, Rb, Cs, etc.) Due to its complex electronic band structure, it exhibits a variety of peculiar quantum effects and has attracted widespread attention in the scientific research community.

[0003] Especially CsV 3 Sb 5 This Kagome metal can exhibit superconducting diode effect in a zero magnetic field environment, providing a theoretical basis for the development of new superconducting diode devices. 3 Sb 5 Plasmon polaritons were first discovered in the study of interaction with light. This discovery not only enhances our understanding of the properties of Kagome metals, but also opens up new paths for the advancement of nano-optics and nanophotonics technology, indicating its potential application value in devices such as super-focusing lenses, waveguides, sensors, tuners, and resonators. In addition, CsV3Sb5 also exhibits a huge anomalous Hall effect, which provides new ideas for the preparation of low-energy electronic components.

[0004] As an important physical phenomenon, the anomalous Hall effect can be regulated in many ways, among which chemical doping is a direct and effective method. 3 Sb 5 The single crystal growth technology of CsV and its dopants faces many challenges. The traditional growth method not only requires the synthesis of precursor flux (such as CsV 3 Sb 5 Requires flux CsSb, Cs 3 Sb 7 or VSb 2 The size of the final single crystal is relatively small, usually only about 1mm×1mm, which seriously limits the in-depth research and large-scale application of Kagome metals.

[0005] The quality and size of the single crystal growth are closely related to the selected growth method. Even if the same growth method is used, slight differences in factors such as the growth process, the choice of co-solvent, and the growth temperature may lead to significant differences in the final results. 3 Sb 5 The (A=K, Rb, Cs) series single crystal growth process is cumbersome and complicated, and the single crystal size is small. There is an urgent need to develop a new, more efficient and controllable single crystal growth method.

[0006] Therefore, the present invention proposes an innovative solution of direct self-solvent method combined with centrifugation method to grow high-quality and large-sized Mn series doped CsV 3 Sb 5 This method not only simplifies the growth process and improves the growth efficiency and repeatability of single crystals, but also provides a solid material foundation for in-depth research on the characteristics of Kagome metals and promoting their practical applications. Summary of the invention

[0007] In view of the above technical problems, the existing CsV 3 Sb 5 The single crystal growth method is cumbersome and complicated, and the obtained single crystal is small, about 1mm×1mm in size. Practical applications and some experiments (such as neutron scattering measurement) require large single crystals, which is difficult to meet the needs. The present invention provides a method for growing Kagome metal AV 3 Sb 5 (A=K,Rb,Cs) single crystal method, especially for Cs(V1-xMnx) 3 Sb 5 The method for growing high-quality large single crystals. This method achieves the effective growth of Kagome metal single crystals through a direct self-solvent method combined with a specific temperature control program, providing an important material basis for in-depth research on quantum phenomena in Kagome lattices, and also provides the possibility for the preparation of low-energy electronic components, superconducting diodes, and nano-optical and photonic devices.

[0008] The technical solution adopted by the present invention to solve the technical problem is: a method for growing Kagome metal AV 3 Sb 5 The method for single crystal, using direct self-solvent method, comprises the following steps:

[0009] S1. Raw material preparation: accurately weigh A, V and Sb raw materials in a molar ratio of 1:3-x:20, wherein A is one of K, Rb or Cs, and x is a value between 0 and 0.3. When x is not 0, additionally weigh an appropriate amount of Mn, and fully grind and mix all the raw materials;

[0010] S2, placing the mixed raw materials in a crucible, sealing in a quartz glass tube, and then performing a heating treatment;

[0011] S3, the heating process includes: heating to 1000°C at a certain rate and maintaining for a period of time, then cooling to 850°C at a faster rate, and then cooling to 680°C at a slower rate;

[0012] S4, at 680 ° C, the crystals were separated from the co-solvent by centrifugation to obtain AV 3 Sb 5 Single crystal.

[0013] The purity of the raw materials A, V, Sb and Mn is not less than 99.5%.

[0014] The time for grinding and mixing the raw materials in step S1 is not less than 15 minutes.

[0015] In the step S2, the quartz glass tube needs to be vacuumed before being sealed and maintained for a period of time.

[0016] In the step S3, the temperature is raised from room temperature to 1000° C. at a rate of 40° C. / h, and maintained at 1000° C. for 20 hours.

[0017] The rate of cooling from 1000° C. to 850° C. in step S3 is 100° C. / h.

[0018] The rate of cooling from 850° C. to 680° C. in step S3 is 1.5° C. / h.

[0019] The rotation speed of the centrifugal treatment in step S4 is 3000 rpm, and the centrifugal time is 15 minutes.

[0020] The method is applicable to growing all AV 3 Sb 5 Single crystals of (A=K, Rb, Cs) system, including but not limited to Cs(V1-xMnx) 3 Sb 5 .

[0021] Adopt a metal AV for growing Kagome 3 Sb 5 Kagome Metal AV obtained by single crystal method 3 Sb 5 The single crystal is a high-quality large single crystal and has a hexagonal block structure.

[0022] The technical effect achieved by the present invention is: the method for growing Kagome metal Cs(V1-xMnx) provided by the present invention 3 Sb 5The single crystal method not only improves the quality and size of the single crystal, but also simplifies the growth process, enhances repeatability and stability, realizes flexible regulation of Mn doping, and broadens the application field. Compared with the existing technology, it has significant advantages and beneficial effects, which are specifically manifested in the following aspects:

[0023] (I) Improving the quality and size of single crystals: By adopting a direct self-solvent method combined with a carefully designed temperature control program, the present invention successfully grew high-quality, large-sized Cs(V1-xMnx) 3 Sb 5 Single crystal. Figure 1 and Figure 2 As shown in Figure 2, these single crystals are not only highly crystalline, but also significantly larger in size than those obtained by traditional methods, which is more conducive to the in-depth exploration of CsV 3 Sb 5 Various physical properties and practical application potential of the system.

[0024] (II) Simplified growth process: The single crystal growth method of the present invention does not require the preparation of complex precursor fluxes, such as CsSb, Cs 3 Sb 7 or VSb 2 This greatly simplifies the growth process and reduces the difficulty and cost of operation. This improvement makes the growth of single crystals more efficient and controllable.

[0025] (III) Enhanced repeatability and stability: By precisely controlling the key steps such as the raw material ratio, the preparation of the crucible and the quartz glass tube, the sealing process, and the heating process, the method of the present invention has extremely high repeatability and stability. This ensures that the Cs(V1-xMnx) that meets the requirements can be obtained each time. 3 Sb 5 Single crystals provide a reliable material basis for further research and application.

[0026] Flexible regulation of Mn doping: The method of the present invention allows flexible regulation of Mn doping concentration by simply adjusting the Mn content (x value) in the raw material. This facilitates the study of the effect of doping on the physical properties of Kagome metals and helps to further explore novel quantum phenomena and potential applications induced by doping.

[0027] (IV) Expanding application areas: high-quality, large-size Cs(V1-xMnx) 3 Sb 5 The successful growth of single crystals provides the possibility to explore the potential applications of Kagome metals in superconducting diodes, nano-optics, nanophotonics, and low-energy electronic components. These single crystals are not only suitable for basic research such as neutron scattering measurements, but may also provide key material support for the development and practical application of new devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The Cs(V 0.97 Mn 0.03 ) 3 Sb 5 Single crystal;

[0029] Figure 2 is Cs(V 1-x Mn x ) 3 Sb 5 Serial single crystal XRD measurement results;

[0030] Figure 3 This is a growth flow chart when x=0.03 in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below with reference to specific embodiments and accompanying drawings:

[0032] like Figure 1-3 Shown, a method for growing Kagome Metal AV 3 Sb 5 The method for single crystal, using direct self-solvent method, comprises the following steps:

[0033] S1. Raw material preparation: accurately weigh A, V and Sb raw materials in a molar ratio of 1:3-x:20, wherein A is one of K, Rb or Cs, and x is a value between 0 and 0.3. When x is not 0, additionally weigh an appropriate amount of Mn, and fully grind and mix all the raw materials; the purity of the raw materials A, V, Sb and Mn is not less than 99.5%; the time for grinding and mixing the raw materials is not less than 15 minutes.

[0034] S2. Place the mixed raw materials in a crucible, seal it in a quartz glass tube, and then heat it; before sealing the quartz glass tube, vacuumize it and keep it for a while. S3. The heating process includes: heating to 1000℃ at a certain rate and keeping it for a while, then cooling to 850℃ at a faster rate, and then cooling to 680℃ at a slower rate; the rate of cooling from 1000℃ to 850℃ is 100℃ / h, the rate of heating from room temperature to 1000℃ is 40℃ / h, and it is kept at 1000℃ for 20 hours; the rate of cooling from 850℃ to 680℃ is 1.5℃ / h.

[0035] S4, at 680 ° C, the crystals were separated from the co-solvent by centrifugation to obtain AV 3 Sb 5 The single crystal, the rotation speed of the centrifugal treatment in step S4 is 3000 rpm, and the centrifugal time is 15 minutes.

[0036] The method is applicable to growing all AV 3 Sb 5 Single crystals of (A=K, Rb, Cs) system, including but not limited to Cs(V1-xMnx) 3 Sb 5 ;Get Kagome Metal AV 3 Sb 5 The single crystal is a high-quality large single crystal and has a hexagonal block structure.

[0037] Example 1: Low-concentration Mn-doped CsV 3 Sb 5 Single crystal growth

[0038] This embodiment aims to grow a low-concentration Mn-doped CsV3Sb5 single crystal by direct self-solvent method, with a specific doping amount of x=0.03, i.e. Cs(V0.97Mn0.03) 3 Sb 5 The single crystal grown in this example is shown in Figure 1 , the flow chart of this embodiment is shown in Figure 3 , as follows:

[0039] Step 1: Raw material preparation

[0040] Accurately weigh Cs, V and Sb raw materials with a molar ratio of 1:3-x:20. When x=0.03, weigh an appropriate amount of Mn, put them into an agate mortar and grind them thoroughly. The grinding time is ≥15 minutes, and the sum of the volumes of all raw materials does not exceed half of the volume that the crucible can accommodate. Ensure that the purity of the raw materials meets the requirements. In this implementation case, Alfa products are selected, and the purity of each component is Cs99.9%, V 99.5%, Mn 99.5%, and Sb 99.6%, in order to reduce the impact of impurities on crystal growth.

[0041] Step 2: Crucible Preparation

[0042] A certain number of alumina crucibles (including crucible lids) were soaked in aqua regia for 2 hours, and then cleaned with deionized water and ultrasonic method. After cleaning, the alumina crucibles and crucible lids were placed into a larger and clean alumina crucible with clean tweezers, and then placed into a muffle furnace together with the crucibles. The temperature was set to 1000°C and baked for 12 hours to remove moisture and impurities.

[0043] Step 3: Preparation of quartz glass tube and quartz column

[0044] Soak the same number of quartz glass tubes and quartz columns as the crucible in aqua regia for 1 hour, then clean them with deionized water and ultrasonic method. After cleaning, use clean tweezers to put the quartz glass tubes and quartz columns into the oven for baking. Before putting them into the oven, lay a layer of aluminum foil on the baking platform of the oven and set the temperature to 120℃ for baking for 12 hours.

[0045] Step 4: Sealing

[0046] Put the crucible with raw materials into the quartz glass tube, add quartz wool and quartz column successively, use long tweezers to push the quartz column to compact the quartz wool, then connect the quartz glass tube to the vacuum interface, tighten the flange, start the vacuum pump to vacuum, open the hydrogen-oxygen welding after 5 minutes of vacuuming, slowly heat the quartz glass tube at the quartz column position for one circle to soften the quartz glass tube and fit tightly with the quartz column, open the flange after cooling and remove the quartz glass tube, cut off the excess quartz glass tube on the upper part of the quartz column so that it can be better placed in the muffle furnace.

[0047] Step 5: Heating process

[0048] First, place the sealed quartz tube into the muffle furnace, pay attention to its position in the furnace, gradually increase the temperature from room temperature to 1000°C at a heating rate of 40°C / h, and maintain this temperature for 20 hours to allow the raw materials to fully melt and react.

[0049] Then, the temperature control system is used to cool the furnace to 850°C at a cooling rate of 100°C / h. In the early stage of crystal growth, rapid cooling to 850°C helps promote the nucleation process of the crystal. Rapid cooling can quickly make the system reach a supersaturated state, which is conducive to the formation of a sufficient number of crystal nuclei and provides a basis for subsequent crystal growth.

[0050] After that, continue to slowly cool to 680℃ at a rate of 1.5℃ / h. After the crystal nucleus is formed, slowly cooling to 680℃ helps the slow growth of the crystal and reduces the generation of crystal defects. Slow cooling gives atoms or molecules enough time to arrange in order, allowing them to gradually grow on the formed crystal nucleus, thereby growing high-quality crystals with good crystallinity.

[0051] Step 6: Crystal separation

[0052] The quartz tube kept at 680°C was carefully and quickly transferred to the centrifuge. The quartz glass tube was inverted. The centrifugal speed was set to 3000 rpm and the centrifugal time was set to 15 minutes. The crystal was separated from the flux by centrifugal force to obtain hexagonal blocks of Cs(V 0.97 Mn 0.03 ) 3 Sb 5 Single crystal.

[0053] In this embodiment, high-quality Cs(V) with good crystallinity was successfully grown by precisely controlling the key steps such as the raw material ratio, the preparation of the crucible and the quartz glass tube, the sealing process, the heating process, and the crystal separation. 0.97 Mn 0.03 ) 3 Sb 5 The single crystal is in the form of a hexagonal block, which is significantly larger than single crystals obtained by traditional methods and has a high degree of crystallinity, which is conducive to in-depth exploration of its physical properties and potential applications.

[0054] Example 2: Medium-concentration Mn-doped CsV 3 Sb 5 Single crystal growth

[0055] The steps of Example 1 were repeated, but in the raw material preparation stage, the doping amount of Mn was changed, for example, x=0.05, to study the influence of different doping concentrations on the crystal properties.

[0056] This example is to further study the effect of different doping concentrations on CsV 3 Sb 5 In this embodiment, the doping amount of Mn is increased to x = 0.05, that is, the growth of Cs (V 0.95 Mn 0.05 ) 3 Sb 5 Single crystal.

[0057] Except for the adjustment of the Mn doping amount in the raw material preparation stage, the other steps are consistent with Example 1. Through careful design and control of the growth process, this example also successfully grew high-quality, medium-concentration Mn-doped CsV 3 Sb 5 The acquisition of this single crystal provides an important material basis for further studying the effect of doping on the physical properties of Kagome metal.

[0058] Example 3: Growth of High-Concentration Mn-Doped CsV3Sb5 Single Crystal

[0059] The steps of Example 1 were repeated, and this time the doping amount of Mn was set to x=0.16, to further explore the relationship between doping concentration and crystal properties. The effectiveness and stability of the method of the present invention were verified by performing structural analysis (such as XRD experiment) and physical property measurement (such as resistivity, magnetic susceptibility, etc.) on the single crystals grown in different embodiments.

[0060] In this example, in order to further explore the effect of Mn doping on CsV 3 Sb 5 Influence of single crystal properties, in this embodiment, the doping amount of Mn is increased to a higher level, that is, x = 0.16, and the growth of Cs (V 0.84 Mn0.16 ) 3 Sb 5 Similarly, except for the adjustment of the Mn doping amount in the raw material preparation stage, the remaining steps strictly follow the description in Example 1. After careful cultivation, this example successfully obtained high-quality, high-concentration Mn-doped CsV 3 Sb 5 Single crystal. This single crystal not only makes it possible to study novel quantum phenomena induced by doping, but also provides an important reference for the development of new functional materials.

[0061] By performing structural analysis (such as XRD experiments) and physical property measurements (such as resistivity, magnetic susceptibility, etc.) on the single crystals grown in the above three embodiments, the effectiveness and stability of the method of the present invention can be verified, and the effect of Mn doping on CsV 3 Sb 5 These examples not only demonstrate the wide applicability of the method of the present invention, but also provide valuable material support for the research and application of Kagome metals.

[0062] The above description is only an implementation case of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention, including but not limited to doping processes, cosolvents, growth processes, etc.

Claims

1. A method for growing a Kagome metal AV3Sb5 single crystal, characterized in that: The direct self-solvent method includes the following steps: S1. Raw material preparation: accurately weigh A, V and Sb raw materials in a molar ratio of 1:3-x:20, wherein A is one of K, Rb or Cs, and x is a value between 0 and 0.

3. When x is not 0, additionally weigh an appropriate amount of Mn, and fully grind and mix all the raw materials; S2, placing the mixed raw materials in a crucible, sealing in a quartz glass tube, and then performing a heating treatment; S3, the heating process includes: heating to 1000°C at a certain rate and maintaining for a period of time, then cooling to 850°C at a faster rate, and then cooling to 680°C at a slower rate; S4. At 680°C, separate the crystal from the co-solvent by centrifugation to obtain AV3Sb5 single crystal.

2. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: The purity of the raw materials A, V, Sb and Mn is not less than 99.5%.

3. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: The time for grinding and mixing the raw materials in step S1 is not less than 15 minutes.

4. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: Before sealing the quartz glass tube in step S2, a vacuum treatment needs to be performed and maintained for a period of time.

5. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: In step S3, the temperature is raised from room temperature to 1000°C at a rate of 40°C / h, and maintained at 1000°C for 20 hours.

6. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: The rate of cooling from 1000°C to 850°C in step S3 is 100°C / h.

7. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: The rate of cooling from 850°C to 680°C in step S3 is 1.5°C / h.

8. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: The rotation speed of the centrifugal treatment in step S4 is 3000 rpm, and the centrifugal time is 15 minutes.

9. A method for growing a Kagome metal AV3Sb5 single crystal according to claim 1, characterized in that: The method is applicable to growing single crystals of all AV3Sb5 (A=K, Rb, Cs) systems, including but not limited to Cs(V1-xMnx)3Sb5.

10. The Kagome metal AV3Sb5 single crystal grown by the method according to any one of claims 1 to 9, characterized in that: The single crystal is a high-quality large single crystal and has a hexagonal block structure.

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