Ultrafast optical storage material screening method based on pseudo slippage and storage device
By constructing heterojunction structures using two-dimensional materials with specific symmetries and band gaps, the pseudoslip effect was verified, solving the problems of reducing power consumption and overcoming material system limitations in existing ultrafast optical storage technologies, and achieving efficient data writing and reading.
Patent Information
- Application Number
- CN202511700607.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-02-27
AI Technical Summary
Existing ultrafast optical storage technologies cannot overcome the limitations of material systems while reducing power consumption, and traditional storage mechanisms lack universality and scalability.
By selecting two-dimensional materials with broken spatial inversion symmetry and band gap within a preset range as driving layers, and selecting two-dimensional materials with unbroken spatial inversion symmetry or band gap larger than that of the driving layer material as substrates, a heterojunction structure is constructed. The pseudoslip effect is verified by photoexcitation simulation, and the optical parameters for data writing and reading are determined.
While reducing power consumption, it overcomes the limitations of material systems, optimizes data writing and reading parameters, and improves storage performance.
Smart Images
Figure CN121583294A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of ultrafast optical storage technology, and in particular to a method for screening ultrafast optical storage materials based on pseudoslip and a storage device. Background Technology
[0002] Ultrafast optical storage technology represents a cutting-edge direction in the field of information storage. Its core concept lies in utilizing the instantaneous high energy density and extremely high temporal resolution of ultrashort laser pulses (such as femtosecond or picosecond lasers) to achieve rapid and reversible control over the microstructure and physical properties of the storage medium, thereby enabling high-speed data writing and reading. Compared to traditional storage mechanisms that rely on charge storage (flash memory) or magnetic domain flipping (disk), optical storage technology, thanks to the ultra-high-speed characteristics of light-matter interaction, can theoretically boost storage speeds to the picosecond or even sub-picosecond level, far exceeding the performance limits of current storage media. With the increasing demands for storage bandwidth and response speed from applications such as artificial intelligence training, real-time big data processing, and high-frequency quantitative trading, the development of new optical storage technologies with ultra-high speed, low latency, and high durability has become an urgent need.
[0003] Among the many material systems suitable for ultrafast optical storage, chalcogenide phase change materials (such as Ge2Sb2Te5, or GST for short) have been widely studied due to their stable phase transition behavior, significant optical and electrical signal contrast, and compatibility with semiconductor processes. These materials can reversibly transition between crystalline and amorphous states, corresponding to high / low reflectivity and resistivity states, respectively, providing the physical signal basis for data storage. Furthermore, a storage strategy utilizing ultrafast laser-induced two-dimensional sliding ferroelectric materials to achieve interlayer slippage has been developed. This strategy achieves state switching through the overall sliding of atomic layers, avoiding the energy-intensive melting process, and leveraging the layered structure of the two-dimensional material to suppress defect migration across layers, thereby improving the device's cycle stability.
[0004] However, the aforementioned technologies still have significant limitations. GST-based solutions require melting to achieve a phase transition, resulting in high energy consumption and limiting their practical application potential. Meanwhile, interlayer slip-based storage strategies are limited by the range of materials available, only applicable to slip ferroelectric materials with specific interlayer coupling characteristics, lacking universality and scalability. Therefore, there is an urgent need to explore a novel storage mechanism that can reduce power consumption while overcoming the limitations of material systems, broadening the range of tunable materials, and providing a feasible technical path for achieving femtosecond-level optical storage devices. Summary of the Invention
[0005] This application provides a method and device for screening ultrafast optical storage materials based on pseudoslip, in order to solve the problem of being unable to overcome the limitations of material systems while reducing power consumption.
[0006] The first aspect of this application provides a method for screening ultrafast optical storage materials based on pseudoslip, the method comprising:
[0007] Acquire crystal structure data of various two-dimensional materials;
[0008] Materials with spatial inversion symmetry broken and band gap within a preset range are selected from the two-dimensional materials as driving layer materials;
[0009] Materials with intact spatial inversion symmetry or with a band gap larger than that of the driving layer material are selected as substrate materials from the two-dimensional materials.
[0010] The driving layer material and the substrate material are subjected to lattice matching treatment to construct a heterojunction structure;
[0011] The heterojunction structure was subjected to photoexcitation simulation, and the laser excitation process was simulated by introducing a time-varying electric field to verify whether the heterojunction structure experienced pseudoslip effect. The laser that drives pseudoslip was used as the optical parameter for data writing.
[0012] Optical properties of heterojunction structures exhibiting pseudoslip are calculated, and the differences in optical properties before and after pseudoslip are compared to determine the optical parameters for data readout.
[0013] The pseudoslip-based ultrafast optical storage material screening method provided in this application constructs heterojunction structures by screening two-dimensional materials with specific symmetry and band gaps, and verifies the pseudoslip effect and changes in optical properties, thereby reducing power consumption and overcoming material system limitations in optical storage applications, and improving storage performance by optimizing data writing and reading parameters.
[0014] Optionally, the crystal structure data is obtained from a two-dimensional material database; the crystal structure data includes the crystal structure, space group number, and band gap data of various two-dimensional materials.
[0015] By directly obtaining crystal structure data containing crystal structure, space group number, and band gap data from a two-dimensional materials database, a reliable data foundation can be provided for subsequent material screening, which helps reduce the workload of data collection and supports the accuracy of the screening process.
[0016] Optionally, the step of selecting materials from the two-dimensional materials that have broken spatial inversion symmetry and have a band gap within a preset range as driving layer materials includes:
[0017] Obtain the spatial group number and band gap data of the two-dimensional materials from the two-dimensional material database;
[0018] By analyzing the spatial group number, it is determined whether the two-dimensional material has a spatial inversion symmetry center, so as to screen out two-dimensional materials that do not have a spatial inversion symmetry center as candidate driving layer materials;
[0019] Based on the bandgap data, candidate driving layer materials with bandgap ranges from 0 electron volts to 4 electron volts were selected as driving layer materials.
[0020] Based on the clearly defined spatial group numbers and bandgap data in the two-dimensional material database, the material selection is carried out by analyzing spatial inversion symmetry and setting bandgap ranges, so as to provide driving layer materials that meet theoretical requirements for subsequent construction of heterostructures, thereby improving the targeting and efficiency of material selection.
[0021] Optionally, the step of selecting materials from the two-dimensional materials that have unbroken spatial inversion symmetry or have a band gap larger than that of the driving layer material as substrate materials includes:
[0022] Obtain the spatial group number and band gap data of the two-dimensional materials from the two-dimensional material database;
[0023] By analyzing the spatial group number, it is determined whether the two-dimensional material has a spatial inversion symmetry center, so as to select two-dimensional materials with a spatial inversion symmetry center as substrate materials;
[0024] Alternatively, a two-dimensional material with a band gap larger than that of the driving layer material can be selected as the substrate material based on the band gap data.
[0025] By setting clear screening criteria for materials with unbroken spatial inversion symmetry or band gaps larger than those of the driving layer material, and performing screening based on spatial group numbers and band gap data in the database, structurally stable and compatible substrate materials are provided for heterojunction structures, thereby improving the adaptability of material combinations and the structural stability of heterojunctions.
[0026] Optionally, the step of performing lattice matching treatment on the driving layer material and the substrate material to construct a heterojunction structure includes:
[0027] The cell expansion direction is selected based on the dimensional properties of the driving layer material and the substrate material;
[0028] Cell expansion operations are performed on the driving layer material and the substrate material;
[0029] The lattice mismatch between the driving layer material and the substrate material is controlled to be less than 4%;
[0030] The interlayer spacing between the driving layer material and the substrate material is set to a preset spacing, and the vacuum layer thickness in the direction perpendicular to the material plane is set to a preset thickness.
[0031] By selecting the cell expansion direction, controlling the lattice mismatch to be less than a preset threshold, and setting the interlayer spacing and vacuum layer thickness, it is helpful to improve the construction quality of heterojunction structures, reduce interface defects, and thus support the accuracy and reliability of subsequent photoexcitation simulations.
[0032] Optionally, after constructing the heterojunction structure, the method further includes:
[0033] From the constructed heterojunction structures, heterojunction structures that satisfy the preset range of in-plane lattice basis angles and the number of atoms are selected.
[0034] The selected heterojunction structures are optimized based on the iterative convergence criterion.
[0035] By adding a screening step based on the in-plane lattice basis vector angle and the number of atoms after constructing the heterojunction structure, and performing structural optimization, the structural quality of the constructed heterojunction can be improved, providing a more reliable model basis for subsequent photoexcitation simulations.
[0036] Optionally, the step of performing photoexcitation simulation on the heterojunction structure and simulating the laser excitation process by introducing a time-varying electric field to verify whether the heterojunction structure undergoes pseudoslip effect, and using the laser that drives the pseudoslip as the optical parameter for data writing, includes:
[0037] A time-varying electric field is constructed to simulate the laser excitation process. The mathematical form of the time-varying electric field is a sine wave with a Gaussian envelope.
[0038] The time-varying electric field is introduced into the Hamiltonian of the quantum system by using a time-dependent vector potential to simulate the excitation process of the heterojunction structure by an ultrashort laser pulse.
[0039] After photoexcitation simulation, the changes in characteristic parameters of the heterojunction structure are analyzed to determine whether the conditions for pseudoslip are met. The conditions include an in-plane structural transformation of the driving layer material and a structural change in the substrate material that is less than a preset threshold.
[0040] Based on the structural evolution analysis results, a combination of driving layer material and substrate material capable of achieving pseudoslip was selected as a candidate system, and the laser wavelength and laser intensity that drive pseudoslip were determined as the optical parameters for data writing.
[0041] By constructing a time-varying electric field to simulate the laser excitation process and analyzing the changes in characteristic parameters of the heterojunction structure, the conditions for the occurrence of pseudoslip effect are verified, thereby screening material combinations that can achieve pseudoslip and determining the optical parameters for data writing, so as to support the accuracy of optical storage material screening and application reliability.
[0042] Optionally, the steps for calculating the optical properties of heterojunction structures exhibiting pseudoslip effects include:
[0043] Calculate the frequency-dependent dielectric constant of the heterojunction structure before pseudoslip occurs;
[0044] The frequency-dependent optical properties in the initial state are calculated based on the frequency-dependent dielectric constant.
[0045] Transformation structures of heterojunctions constructed after pseudoslip occurs;
[0046] Calculate the frequency-dependent optical properties of the transformation structure, including reflectivity and refractive index.
[0047] By calculating the frequency-dependent dielectric constant and optical properties of the heterojunction structure before and after pseudoslip, the changes in parameters such as reflectivity and refractive index are obtained, providing data support for comparing the differences in optical response before and after the structural transformation, thereby helping to determine the optical parameters for data reading.
[0048] Optionally, the steps of comparing the differences in optical properties before and after the pseudoslip to determine the optical parameters for data readout include:
[0049] The frequency-dependent optical properties of the transformed structure are compared with those of the initial state to calculate the difference in optical properties at multiple frequency points.
[0050] Determine whether there exists at least one preset frequency range such that the difference in optical properties exceeds a preset judgment threshold;
[0051] If it exists, the heterojunction structure is determined to be a valid pseudoslip system;
[0052] For a pseudoslip system that is determined to be valid, the frequency point at which the difference in optical properties reaches its maximum is selected as the optical frequency for data reading, and the optical intensity below the critical optical intensity that causes pseudoslip in the heterojunction structure is selected as the optical intensity for data reading.
[0053] By comparing the differences in optical properties of heterojunction structures before and after pseudoslip occurs and setting a judgment threshold, pseudoslip systems with significant changes in optical response can be screened out, and the optical frequency and intensity of data reading can be determined accordingly, thereby improving the discrimination and reliability of data reading operations.
[0054] The second aspect of this application provides an ultrafast optical storage device based on pseudoslip, the device comprising a heterojunction structure composed of a driving layer material and a substrate material selected by the pseudoslip-based ultrafast optical storage material screening method described in the first aspect, an optical system for generating femtosecond laser pulses, and a photoelectric detection system for detecting optical response signals.
[0055] By constructing a heterojunction structure using the driving layer and substrate material obtained through the screening method, and in conjunction with a femtosecond laser pulse optical system and a photoelectric detection system, optical storage function can be directly realized by utilizing the verified pseudoslip effect, thereby reducing device development cycle and experimental costs, and improving the speed and reliability of data writing and reading processes.
[0056] As can be seen from the above technical solutions, this application provides a method and device for screening ultrafast optical storage materials based on pseudoslip. The method involves acquiring crystal structure data of various two-dimensional materials; selecting materials with broken spatial inversion symmetry and band gaps within a preset range as driving layer materials; selecting materials with unbroken spatial inversion symmetry or band gaps larger than the driving layer material as substrate materials; performing lattice matching processing on the driving layer material and the substrate material to construct a heterojunction structure; simulating photoexcitation of the heterojunction structure and simulating the laser excitation process by introducing a time-varying electric field to verify whether the heterojunction structure exhibits a pseudoslip effect, and using the laser that drives the pseudoslip as the optical parameter for data writing; calculating the optical properties of the heterojunction structure exhibiting the pseudoslip effect and comparing the differences in optical properties before and after pseudoslip to determine the optical parameters for data reading, thus solving the problem of not being able to overcome the limitations of the material system while reducing power consumption. Attached Figure Description
[0057] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0058] Figure 1 This is a schematic flowchart of the ultrafast optical storage material screening method based on pseudoslip provided in an embodiment of this application. Detailed Implementation
[0059] The embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described below do not represent all embodiments consistent with this application. They are merely examples of systems and methods consistent with some aspects of this application.
[0060] To address the challenge of overcoming material limitations while reducing power consumption, see [reference needed]. Figure 1 This application provides a method for screening ultrafast optical storage materials based on pseudoslip, the method comprising:
[0061] S100: Acquire crystal structure data for various two-dimensional materials.
[0062] In some embodiments, the crystal structure data is obtained from a two-dimensional material database; the crystal structure data includes the crystal structure, space group number, and band gap data of various two-dimensional materials.
[0063] It should be understood that the two-dimensional material database may be 2DHub, a comprehensive database platform focused on two-dimensional material research. This platform integrates relevant data resources for two-dimensional materials globally, covering information on crystal structure, electronic properties, optical characteristics, mechanical properties, and other aspects. In this application, the 2DHub database can efficiently acquire crystal structure data for various two-dimensional materials, thus providing strong data support for the screening of pseudoslip-based ultrafast optical storage materials. The bandgap data includes bandgap size and other physicochemical properties. These bandgap sizes and other physicochemical properties comprehensively reflect the characteristics of two-dimensional materials in terms of energy band structure and related chemical properties. Bandgap size is a key parameter for measuring the electronic structure of a material, determining its performance in optics, electronics, etc., such as the absorption characteristics of light at different wavelengths and its conductivity. Other physicochemical properties, such as the dielectric constant and thermal stability of the material, help to further evaluate the applicability and stability of two-dimensional materials in practical application environments, providing richer and more comprehensive reference for screening suitable pseudoslip-based ultrafast optical storage materials.
[0064] By directly obtaining crystal structure data containing crystal structure, space group number, and band gap data from a two-dimensional materials database, a reliable data foundation can be provided for subsequent material screening, which helps reduce the workload of data collection and supports the accuracy of the screening process.
[0065] S200: Select materials from the two-dimensional materials that have broken spatial inversion symmetry and have a band gap within a preset range as driving layer materials.
[0066] In some embodiments, the step of selecting materials with broken spatial inversion symmetry and band gap within a preset range from the two-dimensional materials as driving layer materials includes:
[0067] Obtain the spatial group number and band gap data of the two-dimensional materials from the two-dimensional material database.
[0068] By analyzing the spatial group number, it is determined whether the two-dimensional material has a spatial inversion symmetry center, so as to screen out two-dimensional materials that do not have a spatial inversion symmetry center as candidate driving layer materials.
[0069] Based on the bandgap data, candidate driving layer materials with bandgap ranges from 0 electron volts to 4 electron volts were selected as driving layer materials.
[0070] It should be understood that bandgap information provided by a two-dimensional material database can be used to determine whether a material is a semiconductor. The 2DHub database contains bandgap data calculated or measured using various methods (such as GGA, HSE, or experiments). Using the bandgap data provided by the two-dimensional material database, two-dimensional semiconductor materials with bandgap ranges from 0 eV to 4 eV can be screened to ensure that they can be effectively excited by commonly used ultrafast lasers.
[0071] Based on the clearly defined spatial group numbers and bandgap data in the two-dimensional material database, the material selection is carried out by analyzing spatial inversion symmetry and setting bandgap ranges, so as to provide driving layer materials that meet theoretical requirements for subsequent construction of heterostructures, thereby improving the targeting and efficiency of material selection.
[0072] S300: Select materials from the two-dimensional materials whose spatial inversion symmetry is not broken or whose band gap is larger than that of the driving layer material as substrate materials.
[0073] It should be understood that the substrate material, serving as the reference point for the driving layer material, must maintain a relatively stable structure during photoexcitation. Therefore, the band gap of the substrate material should be larger than that of the driving layer material to ensure that only the driving layer is excited and not the substrate; or its structure should remain unchanged after excitation, i.e., it must satisfy spatial inversion symmetry.
[0074] In some embodiments, the step of selecting materials from the two-dimensional materials that have unbroken spatial inversion symmetry or have a band gap larger than that of the driving layer material as substrate materials includes:
[0075] Obtain the spatial group number and band gap data of the two-dimensional materials from the two-dimensional material database.
[0076] By analyzing the spatial group number, it is determined whether the two-dimensional material has a spatial inversion symmetry center, so as to select two-dimensional materials with a spatial inversion symmetry center as substrate materials.
[0077] It should be understood that by querying the space group number of the material and analyzing its symmetry characteristics, materials with spatial inversion symmetry centers are selected as substrate material candidates to ensure that the structure remains unchanged during the excitation process.
[0078] Alternatively, a two-dimensional material with a band gap larger than that of the driving layer material can be selected as the substrate material based on the band gap data.
[0079] It should be understood that bandgap data (such as GGA, HSE, or experimental measurements) provided by the 2DHub database can be used to screen for two-dimensional materials with band gaps larger than those of the driving layer material, so as to ensure that only the driving layer is excited and the substrate is not excited.
[0080] By setting clear screening criteria for materials with unbroken spatial inversion symmetry or band gaps larger than those of the driving layer material, and performing screening based on spatial group numbers and band gap data in the database, structurally stable or compatible substrate materials are provided for heterojunction structures, thereby improving the adaptability of material combinations and the structural stability of heterojunctions.
[0081] S400: The driving layer material and the substrate material are subjected to lattice matching treatment to construct a heterojunction structure.
[0082] It should be understood that, since the lattice constants of the driving layer material and the substrate material are usually mismatched, cell expansion operations are required using tools such as VASPKit to construct heterojunction structures.
[0083] In some embodiments, the step of performing lattice matching processing on the driving layer material and the substrate material to construct a heterojunction structure includes:
[0084] The cell expansion direction is selected based on the dimensional characteristics of the driving layer material and the substrate material.
[0085] Cell expansion operations are performed on the driving layer material and the substrate material.
[0086] The lattice mismatch between the driving layer material and the substrate material is controlled to be less than 4%.
[0087] The interlayer spacing between the driving layer material and the substrate material is set to a preset spacing, and the vacuum layer thickness in the direction perpendicular to the material plane is set to a preset thickness.
[0088] It should be understood that for two-dimensional materials, it is preferable to extend the material plane in two directions, and retaining a certain vacuum layer in the direction perpendicular to the material plane can avoid interlayer interactions. A 4% lattice mismatch ensures that strain has a small impact on the two layers. The preset spacing between the driving layer material and the substrate material can be set to 3.5 angstroms, and the preset thickness of the vacuum layer can be set to 15 angstroms.
[0089] By selecting the cell expansion direction, controlling the lattice mismatch to be less than a preset threshold, and setting the interlayer spacing and vacuum layer thickness, it is helpful to improve the construction quality of heterojunction structures, reduce interface defects, and thus support the accuracy and reliability of subsequent photoexcitation simulations.
[0090] In some embodiments, after constructing the heterojunction structure, the method further includes:
[0091] From the constructed heterojunction structures, heterojunction structures that satisfy the preset range of in-plane lattice basis angles and the number of atoms are selected.
[0092] It should be understood that the preset in-plane lattice basis vector angle range can be 60°-120°, and the threshold for the total number of atoms can be 100-200 atoms.
[0093] The selected heterojunction structures are optimized based on the iterative convergence criterion, including optimizing the interlayer spacing of the driving layer material and the substrate material.
[0094] It should be understood that structural optimization should follow iterative convergence criteria, such as setting the force convergence criterion. The energy convergence criterion is set at 10. -6 eV, to ensure that the system is at its lowest energy point after optimization, and to eliminate unstable structures.
[0095] By adding a screening step based on the in-plane lattice basis vector angle and the number of atoms after constructing the heterojunction structure, and performing structural optimization, the structural quality of the constructed heterojunction can be improved, providing a more reliable model basis for subsequent photoexcitation simulations.
[0096] S500: Perform photoexcitation simulation on the heterojunction structure, and simulate the laser excitation process by introducing a time-varying electric field to verify whether the heterojunction structure has a pseudoslip effect, and use the laser that drives the pseudoslip as the optical parameter for data writing.
[0097] It should be understood that, in order to verify whether the constructed heterojunction structure can serve as a storage cell and to design the optical parameters for data writing, it is necessary to examine under what form of optical field can pseudoslip be achieved. Pseudoslip is characterized by activating only the optical phonons of the driving layer under the action of an optical field to achieve a slip-like motion relative to the substrate layer, while the geometric center of the driving layer remains unchanged.
[0098] In some embodiments, the steps of performing photoexcitation simulation on the heterojunction structure and simulating the laser excitation process by introducing a time-varying electric field to verify whether the heterojunction structure undergoes pseudoslip effect, and using the laser that drives the pseudoslip as the optical parameter for data writing, include:
[0099] A time-varying electric field is constructed to simulate the laser excitation process. The mathematical form of the time-varying electric field is a sine wave with a Gaussian envelope.
[0100] It should be understood that, for the simulation of photoexcitation, the magnetic field component of the light (i.e., electromagnetic wave) can be ignored because its influence on structural dynamics is usually negligible; only the electric field component is retained. The mathematical form of the time-varying electric field is a sine wave with a Gaussian envelope, and its formula is:
[0101]
[0102] Where E(t) represents the electric field evolving with time t, E0 represents the electric field strength, ω represents the photon frequency, t0 represents the center moment of the Gaussian function peak, and σ is used to characterize the broadening of the Gaussian function.
[0103] The time-varying electric field is introduced into the Hamiltonian of the quantum system by a time-dependent vector potential to simulate the excitation process of the heterojunction structure by an ultrashort laser pulse.
[0104] The influence of the electric field is transmitted to the quantum system through a time-dependent vector potential, as shown in the following formula:
[0105]
[0106] Where A(t) represents the gauge field vector potential introduced by the electric field. To simulate the structural dynamics after photoexcitation, an A field is added to the Hamiltonian of the reciprocal space, and its formula is:
[0107]
[0108] Where H(t) is the time-dependent Hamiltonian, It is a momentum operator.
[0109] Through the above process, the influence of the light field is introduced into the quantum system, thereby enabling the simulation of the excitation process of heterojunction structures by lasers of different wavelengths and intensities.
[0110] After photoexcitation simulation, the changes in characteristic parameters of the heterojunction structure are analyzed to determine whether the conditions for pseudoslip are met. These conditions include an in-plane structural transformation of the driving layer material and a structural change in the substrate material that is less than a preset threshold.
[0111] Based on the structural evolution analysis results, a combination of driving layer material and substrate material capable of achieving pseudoslip was selected as a candidate system, and the laser wavelength and laser intensity that drive pseudoslip were determined as the optical parameters for data writing.
[0112] It should be understood that in the mechanism of displacement-induced coherent phonon excitation, photons excite valence band electrons to the conduction band, and then, through electro-acoustic coupling, gradually transfer energy to the phonons to drive structural transitions. Typically, in materials with broken spatial inversion symmetry, photoexcitation will drive structural transitions along the broken direction. Therefore, the structural characteristic parameters of the system after photoexcitation can be analyzed to determine whether pseudoslip occurs, i.e., whether the driving layer material undergoes an in-plane structural transition while the substrate material structure remains essentially unchanged. Therefore, a preset threshold can be set where the change in specific structural parameters of the substrate material is within a very small range, serving as the basis for judging whether the structural change of the substrate material is less than the preset threshold.
[0113] By constructing a time-varying electric field to simulate the laser excitation process and analyzing the changes in characteristic parameters of the heterojunction structure, the conditions for the occurrence of pseudoslip effect are verified, thereby screening material combinations that can achieve pseudoslip and determining the optical parameters for data writing, so as to support the accuracy of optical storage material screening and application reliability.
[0114] S600: Calculate the optical properties of heterojunction structures exhibiting pseudoslip effect and compare the differences in optical properties before and after pseudoslip to determine the optical parameters for data readout.
[0115] It should be understood that, in order to verify whether the constructed pseudoslip system can serve as a storage unit and to design the optical parameters for data reading, a distinguishable signal contrast needs to be generated after optical manipulation to correspond to the storage states "0" and "1". Therefore, various property calculations of the system are required to confirm the differences before and after pseudoslip and to determine the signal reading method accordingly.
[0116] In some embodiments, the step of calculating the optical properties of a heterojunction structure exhibiting pseudoslip includes:
[0117] Calculate the frequency-dependent dielectric constant of the heterojunction structure before pseudoslip occurs.
[0118] The frequency-dependent optical properties in the initial state are calculated based on the frequency-dependent dielectric constant.
[0119] Transformation structures of heterojunctions constructed after pseudoslip occurs.
[0120] Calculate the frequency-dependent optical properties of the transformation structure, including reflectivity and refractive index.
[0121] By calculating the frequency-dependent dielectric constant and optical properties of the heterojunction structure before and after pseudoslip, the changes in parameters such as reflectivity and refractive index are obtained, providing data support for comparing the differences in optical response before and after the structural transformation, thereby helping to determine the optical parameters for data reading.
[0122] In some embodiments, the step of comparing the differences in optical properties before and after the pseudoslip to determine the optical parameters for data reading includes:
[0123] The frequency-dependent optical properties of the transformed structure are compared with those of the initial state to calculate the difference in optical properties at multiple frequency points.
[0124] Determine whether there exists at least one preset frequency range such that the difference in optical properties exceeds a preset judgment threshold;
[0125] If it exists, the heterojunction structure is determined to be a valid pseudoslip system;
[0126] For a pseudoslip system that is determined to be valid, the frequency point at which the difference in optical properties reaches its maximum is selected as the optical frequency for data reading, and the optical intensity below the critical optical intensity that causes pseudoslip in the heterojunction structure is selected as the optical intensity for data reading.
[0127] By comparing the differences in optical properties of heterojunction structures before and after pseudoslip occurs and setting a judgment threshold, pseudoslip systems with significant changes in optical response can be screened out, and the optical frequency and intensity of data reading can be determined accordingly, thereby improving the discrimination and reliability of data reading operations.
[0128] The pseudoslip-based ultrafast optical storage material screening method provided in this application constructs heterojunction structures by screening two-dimensional materials with specific symmetry and band gaps, and verifies the pseudoslip effect and changes in optical properties, thereby reducing power consumption and overcoming material system limitations in optical storage applications, and improving storage performance by optimizing data writing and reading parameters.
[0129] This application also provides a pseudoslip-based ultrafast optical storage device, which includes a heterojunction structure composed of a driving layer material and a substrate material selected by the pseudoslip-based ultrafast optical storage material screening method described in the above embodiments, as well as an optical system for generating femtosecond laser pulses and a photoelectric detection system for detecting optical response signals.
[0130] It should be understood that in this pseudoslip-based ultrafast optical storage device, the heterojunction structure composed of the driving layer material and the substrate material is the core component for realizing ultrafast optical storage. Obtained through the aforementioned screening method, it possesses specific symmetry and bandgap, enabling significant pseudoslip effects and changes in optical properties. The optical system used to generate femtosecond laser pulses can provide precise and stable femtosecond laser pulses, providing a suitable excitation source for the heterojunction structure. The photodetector system used to detect the optical response signal can sensitively capture the optical response signal of the heterojunction structure under femtosecond laser pulse excitation, thereby achieving precise control of the optical storage process and data reading. By constructing a heterojunction structure using the driving layer and substrate materials obtained through the aforementioned screening method, and in conjunction with the femtosecond laser pulse optical system and photodetector system, the verified pseudoslip effect can be directly utilized to achieve optical storage functionality, thereby reducing device development cycle and experimental costs, and improving the speed and reliability of data writing and reading processes.
[0131] As can be seen from the above technical solutions, the embodiments of this application provide a method and storage device for screening ultrafast optical storage materials based on pseudoslip. This involves acquiring crystal structure data of various two-dimensional materials; selecting materials from the two-dimensional materials with broken spatial inversion symmetry and band gaps within a preset range as driving layer materials; selecting materials from the two-dimensional materials with unbroken spatial inversion symmetry or band gaps larger than the driving layer material as substrate materials; performing lattice matching processing on the driving layer material and the substrate material to construct a heterojunction structure; simulating photoexcitation on the heterojunction structure and simulating the laser excitation process by introducing a time-varying electric field to verify whether the heterojunction structure exhibits a pseudoslip effect, and using the laser that drives the pseudoslip as the optical parameter for data writing; calculating the optical properties of the heterojunction structure exhibiting the pseudoslip effect and comparing the differences in optical properties before and after pseudoslip to determine the optical parameters for data reading, thus solving the problem of not being able to overcome the limitations of the material system while reducing power consumption.
[0132] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.
Claims
1. A method for screening ultrafast optical storage materials based on pseudoslip, characterized in that, The method includes: Acquire crystal structure data of various two-dimensional materials; Materials with spatial inversion symmetry broken and band gap within a preset range are selected from the two-dimensional materials as driving layer materials; Materials with intact spatial inversion symmetry or with a band gap larger than that of the driving layer material are selected as substrate materials from the two-dimensional materials. The driving layer material and the substrate material are subjected to lattice matching treatment to construct a heterojunction structure; The heterojunction structure was subjected to photoexcitation simulation, and the laser excitation process was simulated by introducing a time-varying electric field to verify whether the heterojunction structure experienced pseudoslip effect. The laser that drives pseudoslip was used as the optical parameter for data writing. Optical properties of heterojunction structures exhibiting pseudoslip are calculated, and the differences in optical properties before and after pseudoslip are compared to determine the optical parameters for data readout.
2. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 1, characterized in that, The crystal structure data is obtained from a two-dimensional material database; the crystal structure data includes the crystal structure, space group number, and band gap data of various two-dimensional materials.
3. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 2, characterized in that, The step of selecting materials with broken spatial inversion symmetry and band gap within a preset range from the two-dimensional materials as driving layer materials includes: Obtain the spatial group number and band gap data of the two-dimensional materials from the two-dimensional material database; By analyzing the spatial group number, it is determined whether the two-dimensional material has a spatial inversion symmetry center, so as to screen out two-dimensional materials that do not have a spatial inversion symmetry center as candidate driving layer materials; Based on the bandgap data, candidate driving layer materials with bandgap ranges from 0 electron volts to 4 electron volts were selected as driving layer materials.
4. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 3, characterized in that, The step of selecting materials from the two-dimensional materials that have unbroken spatial inversion symmetry or have a band gap larger than that of the driving layer material as substrate materials includes: Obtain the spatial group number and band gap data of the two-dimensional materials from the two-dimensional material database; By analyzing the spatial group number, it is determined whether the two-dimensional material has a spatial inversion symmetry center, so as to select two-dimensional materials with a spatial inversion symmetry center as substrate materials; Alternatively, a two-dimensional material with a band gap larger than that of the driving layer material can be selected as the substrate material based on the band gap data.
5. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 1, characterized in that, The step of performing lattice matching processing on the driving layer material and the substrate material to construct a heterojunction structure includes: The cell expansion direction is selected based on the dimensional properties of the driving layer material and the substrate material; Cell expansion operations are performed on the driving layer material and the substrate material; The lattice mismatch between the driving layer material and the substrate material is controlled to be less than 4%; The interlayer spacing between the driving layer material and the substrate material is set to a preset spacing, and the vacuum layer thickness in the direction perpendicular to the material plane is set to a preset thickness.
6. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 1, characterized in that, After constructing the heterojunction structure, the method further includes: From the constructed heterojunction structures, heterojunction structures that satisfy the preset range of in-plane lattice basis angles and the number of atoms are selected. The selected heterojunction structures are optimized based on the iterative convergence criterion.
7. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 1, characterized in that, The steps of performing photoexcitation simulation on the heterojunction structure, simulating the laser excitation process by introducing a time-varying electric field to verify whether the heterojunction structure exhibits a pseudoslip effect, and using the laser driving the pseudoslip as the optical parameter for data writing include: A time-varying electric field is constructed to simulate the laser excitation process. The mathematical form of the time-varying electric field is a sine wave with a Gaussian envelope. The time-varying electric field is introduced into the Hamiltonian of the quantum system by using a time-dependent vector potential to simulate the excitation process of the heterojunction structure by an ultrashort laser pulse. After photoexcitation simulation, the changes in characteristic parameters of the heterojunction structure are analyzed to determine whether the conditions for pseudoslip are met. The conditions include an in-plane structural transformation of the driving layer material and a structural change in the substrate material that is less than a preset threshold. Based on the structural evolution analysis results, a combination of driving layer material and substrate material capable of achieving pseudoslip was selected as a candidate system, and the laser wavelength and laser intensity that drive pseudoslip were determined as the optical parameters for data writing.
8. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 1, characterized in that, The steps for calculating the optical properties of heterojunction structures exhibiting pseudoslip include: Calculate the frequency-dependent dielectric constant of the heterojunction structure before pseudoslip occurs; The frequency-dependent optical properties in the initial state are calculated based on the frequency-dependent dielectric constant. Transformation structures of heterojunctions constructed after pseudoslip occurs; Calculate the frequency-dependent optical properties of the transformation structure, including reflectivity and refractive index.
9. The method for screening ultrafast optical storage materials based on pseudoslip according to claim 8, characterized in that, The steps for comparing the differences in optical properties before and after the pseudoslip to determine the optical parameters for data readout include: The frequency-dependent optical properties of the transformed structure are compared with those of the initial state to calculate the difference in optical properties at multiple frequency points. Determine whether there exists at least one preset frequency range such that the difference in optical properties exceeds a preset judgment threshold; If it exists, the heterojunction structure is determined to be a valid pseudoslip system; For a pseudoslip system that is determined to be valid, the frequency point at which the difference in optical properties reaches its maximum is selected as the optical frequency for data reading, and the optical intensity below the critical optical intensity that causes pseudoslip in the heterojunction structure is selected as the optical intensity for data reading.
10. An ultrafast optical storage device based on pseudoslip, characterized in that, The device includes a heterojunction structure composed of a driving layer material and a substrate material selected by the pseudoslip-based ultrafast optical storage material screening method according to any one of claims 1-9, an optical system for generating femtosecond laser pulses, and a photoelectric detection system for detecting optical response signals.