Method for regulating copper indium thiophosphate to generate polarization skyrmion through electric field and application thereof

Abstract

The invention relates to a method for generating polarization skyrmion by regulating and controlling copper-indium thiophosphate through an electric field and application thereof, the method comprises the following steps: preparing copper-indium thiophosphate through a chemical vapor transport method, the molecular formula of the copper-indium thiophosphate is Cu1-xInP2S6, x is greater than or equal to 0.28 and greater than or equal to 0.15, and the copper-indium thiophosphate has a ferroelectric domain; preparing the copper indium thiophosphate into a nano film through a mechanical stripping technology; placing the nano-film on the surface of the substrate through a dry transfer technology; the piezoelectric response force microscope technology is utilized, voltage is applied to the surface of the nano-film through the needle tip to form an electric field, the ferroelectric domain is converted into the polarized skyrmion, the direction of the electric field is perpendicular to the nano-film, the nano-film points to the needle tip, and the intensity is 20 V / mu m-40 V / mu m. According to the method, conversion from the ferroelectric domain to the polarized skyrmion can be effectively regulated and controlled under the condition that the lattice structure and the morphology of the copper indium thiophosphate are not influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic materials, and in particular to a method for generating polarized skyrmions by regulating copper indium thiophosphate through an electric field, and applications thereof. Background Art

[0002] Skyrmions, topological domain structures with a continuously rotating polarization structure, typically exist in specific ferroelectric materials. They have attracted widespread attention due to their potential applications in high-density, low-power information storage devices, such as ferroelectric memories and high-speed memristors. Conventional techniques for manipulating polarized skyrmions in ferroelectric materials rely primarily on chemical doping and external stress. However, it should be noted that both chemical doping and external stress can adversely affect the lattice structure and morphology of ferroelectric materials, thereby affecting their ferroelectric properties and hindering the development of ferroelectric memories and high-speed memristor technologies based on copper indium thiophosphate (CIPS). Therefore, there is an urgent need to develop methods for manipulating the generation of polarized skyrmions. Summary of the Invention

[0003] Based on this, it is necessary to provide a method and application of producing polarized skyrmions in copper indium thiophosphate by regulating the electric field to address the above problems. This method can effectively regulate the transformation of ferroelectric domains in copper indium thiophosphate into polarized skyrmions without affecting the lattice structure and morphology of copper indium thiophosphate.

[0004] The present invention discloses a method for generating polarized skyrmions by regulating copper indium thiophosphate through an electric field, comprising the following steps:

[0005] Copper indium thiophosphate is prepared by chemical vapor transport, wherein the molecular formula of the copper indium thiophosphate is Cu 1-x InP2S6, 0.28>x≥0.15, the copper indium thiophosphate has ferroelectric domains;

[0006] preparing the copper indium thiophosphate into a copper indium thiophosphate nanofilm by mechanical stripping technology;

[0007] placing the copper indium thiophosphate nanofilm on the surface of the substrate by dry transfer technology;

[0008] Using piezoelectric response force microscopy technology, a voltage is applied to the surface of the copper indium thiophosphate nanofilm through a needle tip to form an electric field, and the ferroelectric domains are converted into polarized skyrmions. The direction of the electric field is perpendicular to the copper indium thiophosphate nanofilm and points from the copper indium thiophosphate nanofilm to the needle tip, with an intensity of 20V / μm-40V / μm.

[0009] In one embodiment, the copper indium thiophosphate nanofilm has a thickness of 40 nm to 80 nm.

[0010] In one embodiment, the voltage is a DC voltage, the direction of the DC voltage is perpendicular to the copper indium thiophosphate nanofilm, and is directed from the copper indium thiophosphate nanofilm to the needle tip, with a magnitude of 1V-2V.

[0011] In one embodiment, the voltage further includes an AC voltage, and the AC voltage has a magnitude of 0.3V-0.5V.

[0012] In one embodiment, in the step of applying an electric field to the surface of the copper indium thiophosphate nanofilm via a needle tip, the scanning frequency is 1.0 Hz-2.0 Hz.

[0013] In one embodiment, the substrate is selected from a gold-coated silicon substrate.

[0014] In one embodiment, the step of preparing copper indium thiophosphate by chemical vapor transport includes growing a copper source, an indium source, a phosphorus source, and a sulfur source in a molar ratio of (0.90-1.15):1:2:6 under heating and vapor transport medium conditions to obtain copper indium thiophosphate.

[0015] In one embodiment, a reaction device for performing chemical vapor transport method includes a source zone and a growth zone, wherein the heating temperature of the source zone is 740°C-760°C, and the heating temperature of the growth zone is 690°C-710°C.

[0016] In one embodiment, the polariton skyrmions have a lateral size of 75 nm to 85 nm and a longitudinal size of 180 nm to 220 nm.

[0017] The present invention discloses an application of the above-mentioned method of generating polarized skyrmions by regulating copper indium thiophosphate through electric field in memory or logical operation.

[0018] In the method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field disclosed in the present invention, copper indium thiophosphate is first prepared by chemical vapor transport technology. The molecular formula of copper indium thiophosphate is Cu 1-xInP2S6, where 0.28>x≥0.15, causes ferroelectric domains to spontaneously appear in copper indium thiophosphate. The copper indium thiophosphate is then formed into a copper indium thiophosphate nanofilm and transferred to a substrate surface. Finally, using piezoresponse force microscopy (PFM) technology, a specific electric field is applied to the surface of the copper indium thiophosphate nanofilm via a needle tip, causing copper ions to migrate to the surface of the copper indium thiophosphate nanofilm. The increased copper ion concentration on the surface induces the transformation of the ferroelectric domains into polarized skyrmions. Because the needle tip only taps or contacts the surface of the copper indium thiophosphate nanofilm, no external stress is generated, and no chemical doping is required. Therefore, the transformation of the ferroelectric domains in the copper indium thiophosphate nanofilm into polarized skyrmions can be effectively controlled without affecting the lattice structure and morphology of the copper indium thiophosphate. In addition, the method provided by the present invention is simple and easy to control, providing a potential feasible solution for the development of memory or logic operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the method for generating polarized skyrmions in copper indium thiophosphate by electric field manipulation;

[0021] Figure 2 Schematic diagram of the structure of polarized skyrmions;

[0022] Figure 3 Surface micromorphology of copper indium thiophosphate in Example 1 and in-plane and out-of-plane polarization images.

[0023] In the figure, 10, copper indium thiophosphate nanofilm; 20, substrate; 201, silicon substrate; 202, gold-plated layer; 30, piezoelectric response force microscope; 301, needle tip. DETAILED DESCRIPTION

[0024] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments or examples and are not intended to limit the present invention.

[0026] The first aspect of the present invention, as Figure 1 As shown, a method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field is provided, comprising the following steps:

[0027] S10, preparing copper indium thiophosphate by chemical vapor transport, wherein the molecular formula of copper indium thiophosphate is Cu 1-x InP2S6, 0.28>x≥0.15, copper indium thiophosphate with ferroelectric domains;

[0028] S20, preparing the copper indium thiophosphate into a copper indium thiophosphate nanofilm 10 by mechanical exfoliation technology;

[0029] S30, placing the copper indium thiophosphate nanofilm 10 on the surface of the substrate 20 by dry transfer technology;

[0030] S40, using piezoelectric response force microscopy technology, a voltage is applied to the surface of the copper indium thiophosphate nanofilm 10 through the needle tip 301 to form an electric field, and the ferroelectric domains are converted into polarized skyrmions, wherein the direction of the electric field is perpendicular to the copper indium thiophosphate nanofilm 10, and is directed from the copper indium thiophosphate nanofilm 10 to the needle tip 301, and the intensity is 20V / μm-40V / μm.

[0031] In step S10, copper indium thiophosphate is prepared by chemical vapor transport technology, which can well control the molecular formula of copper indium thiophosphate to be Cu 1-x InP2S6, 0.28>x≥0.15, resulting in the spontaneous emergence of ferroelectric domains in copper indium thiophosphate. It should be noted that when 0.28>x≥0.15, the spontaneously emerging ferroelectric domains in copper indium thiophosphate have regular shapes, such as long strips. If x≤0.15, no ferroelectric domains appear in the copper indium thiophosphate, making it impossible to control the transformation of ferroelectric domains to polariton skyrmions through electric field. If x≥0.28, the ferroelectric domains become irregular and cannot be transformed into polariton skyrmions under the action of an electric field.

[0032] In one embodiment, the step of preparing copper indium thiophosphate by chemical vapor transport includes growing a copper source, an indium source, a phosphorus source, and a sulfur source in a molar ratio of (0.90-1.15):1:2:6 under heating and a vapor transport medium to obtain copper indium thiophosphate. It should be noted that the chemical vapor transport method relies on the transmission of elements in the gas phase, and the transmission efficiency of copper is relatively low. Especially at high temperatures, copper may form a relatively stable compound through a gas phase reaction, so that the copper transported in the gas phase is reduced, resulting in a decrease in its proportion in the final product. Therefore, the molecular formula of the prepared copper indium thiophosphate is Cu 1-x InP2S6, 0.28>x≥0.15.

[0033] In one embodiment, a reaction apparatus for performing a chemical vapor transport method includes a source region and a growth region, wherein the heating temperature of the source region is preferably 740°C-760°C to avoid copper loss due to volatilization, and the heating temperature of the growth region is preferably 690°C-710°C; thereby, while promoting copper deposition, copper volatilization or the formation of volatile compounds is avoided. Thus, by precisely controlling the temperature of the source region and the temperature of the growth region, the copper content in the copper indium thiophosphate can be more accurately controlled.

[0034] In step S20, copper indium thiophosphate is made into a copper indium thiophosphate nanofilm 10. The present invention does not limit the step of making copper indium thiophosphate into copper indium thiophosphate nanofilm 10. In one embodiment, copper indium thiophosphate is made into copper indium thiophosphate nanofilm 10 by repeatedly sticking and then tearing the copper indium thiophosphate with tape. Since the layers of copper indium thiophosphate are connected to each other by van der Waals action, the action force is less than the adhesion force of the tape. Therefore, by repeatedly sticking and tearing the tape, the thickness of the copper indium thiophosphate nanofilm 10 can be reduced to the nanometer level to obtain the copper indium thiophosphate nanofilm 10. Preferably, the thickness of the copper indium thiophosphate nanofilm 10 is 40nm-80nm, including but not limited to 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm or 80nm.

[0035] In step S30, the copper indium thiophosphate nanofilm 10 is transferred to the surface of the substrate 20. The present invention does not limit the step of transferring the copper indium thiophosphate nanofilm 10 to the surface of the substrate 20. In one embodiment, the step uses an organic silicon polymer as a medium to transfer the copper indium thiophosphate nanofilm 10 to the surface of the substrate 20. The organic silicon polymer includes but is not limited to at least one of polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE) or polyimide (PI).

[0036] In one embodiment, the substrate 20 is selected from a gold-plated silicon substrate. It can be understood that the gold-plated silicon substrate includes a stacked silicon substrate 201 and a gold-plated layer 202, so as to better avoid excessive accumulation of charge on the surface of the copper indium thiophosphate, which makes testing difficult; preferably, before the step of transferring the copper indium thiophosphate nanofilm 10 to the surface of the substrate 20, the substrate 20 is first treated with ultrasonic cleaning.

[0037] Step S40 utilizes piezoresponse force microscopy technology, such as Figure 1 As shown, a specific electric field is applied to the surface of the copper indium thiophosphate nanofilm 10 via the tip 301 of a piezoresistive force microscope 30. Because the metal support used to support the substrate 20 and the copper indium thiophosphate nanofilm 10 in the piezoresistive force microscope 30 is grounded via internal wires within the instrument, a capacitive structure is formed between the tip 301 and the substrate 20, with the copper indium thiophosphate nanofilm 10 positioned in the middle. Consequently, an electric field is generated within the copper indium thiophosphate nanofilm 10. Under the action of the electric field, copper ions migrate to the surface of the nanofilm, inducing a transformation of ferroelectric domains into a complex domain state with a polarized skyrmion topology. Because the tip 301 only taps or contacts the surface of the copper indium thiophosphate nanofilm 10, no external stress is generated, and no chemical doping is required. Therefore, the transformation of ferroelectric domains into polarized skyrmions in the copper indium thiophosphate nanofilm 10 can be effectively controlled without affecting the lattice structure and morphology of the copper indium thiophosphate.

[0038] In one embodiment, the voltage is a direct current (DC) voltage, the direction of which is perpendicular to the copper indium thiophosphate nanofilm 10 and directed from the copper indium thiophosphate nanofilm 10 toward the needle tip 301, and the magnitude is 1V-2V. It should be noted that if the direction of the DC voltage is changed, i.e., if the DC voltage is controlled to be perpendicular to the copper indium thiophosphate nanofilm 10 and directed from the needle tip 301 toward the copper indium thiophosphate nanofilm 10, the copper ion concentration on the surface of the copper indium thiophosphate nanofilm 10 decreases, and the ferroelectric domains cannot be effectively converted into polarized skyrmions.

[0039] In one embodiment, the voltage further includes an AC voltage, and the AC voltage has a magnitude of 0.3V-0.5V; the main function of the AC voltage is imaging and testing the generation of polarized skyrmions.

[0040] In one embodiment, in the step of applying an electric field on the surface of the copper indium thiophosphate nanofilm 10 through the needle tip 301 , the scanning frequency is 1.0 Hz-2.0 Hz.

[0041] In one embodiment, if Figure 2 As shown, the lateral size of the polariton skyrmions is 75nm-85nm, and the longitudinal size is 180nm-220nm.

[0042] A second aspect of the present invention provides an application of the above-mentioned method of generating polarized skyrmions by regulating copper indium thiophosphate through electric field in memory or logic operations.

[0043] Polarized skyrmions, due to their unique stability and tiny size, have become a promising option for high-density storage. By manipulating copper indium thiophosphate with an electric field to generate polarized skyrmions, the electrical resistance of the material can be controlled, enabling the manipulation and reading of information, ultimately achieving high-density storage.

[0044] In practical applications, applying an electric field to manipulate the generation of polarized skyrmions in copper indium thiophosphate (CITP) allows the resistance state properties of these polarized skyrmions to be used to read stored information. Because the presence of polarized skyrmions changes the resistivity of the CITP, the "0" and "1" states in the CITP can be read by measuring this resistance change. This resistance-based reading method offers the advantages of high sensitivity and low power consumption, making it ideal for high-density storage devices. Therefore, manipulating the generation of polarized skyrmions in CITP through electric fields and subsequently changing the resistance state provides a new technical path for achieving high-density storage and is expected to play a key role in future storage technologies.

[0045] Hereinafter, a method for generating polarized skyrmions by regulating copper indium thiophosphate through an electric field and its application will be further described through the following specific examples.

[0046] Example 1

[0047] Copper indium thiophosphate is grown in a molar ratio of 1:1:2:6 by heating copper powder, indium block, phosphorus block and sulfur powder under the conditions of gas phase transport medium. The reaction device for chemical vapor transport method includes a source area and a growth area. The heating temperature of the source area is 750℃ and the heating temperature of the growth area is 700℃. The molecular formula of the obtained copper indium thiophosphate is Cu 0.82 InP2S6, i.e., x = 0.18, copper indium thiophosphate with ferroelectric domains.

[0048] Copper indium thiophosphate was repeatedly pasted and then torn with tape to form a copper indium thiophosphate nanofilm 10 with a thickness of 60nm±5nm. The copper indium thiophosphate nanofilm 10 was transferred to the surface of a gold-coated silicon substrate using polydimethylsiloxane as a medium.

[0049] Using piezoelectric response force microscopy technology, a DC voltage is applied to the surface of the copper indium thiophosphate nanofilm 10 through the needle tip 301 to form an electric field, so that the ferroelectric domains are converted into polarized skyrmions, and copper indium thiophosphate with polarized skyrmions is obtained. The direction of the electric field is perpendicular to the copper indium thiophosphate nanofilm 10, pointing from the copper indium thiophosphate nanofilm 10 to the needle tip 301, with an intensity of 32V / μm and a scanning frequency of 1.57Hz. While applying the DC voltage, an AC voltage of 0.3V is also applied for imaging to detect the generation of ferroelectric domains and polarized skyrmions.

[0050] Comparative Example 1

[0051] Comparative Example 1 was carried out with reference to Example 1, except that the intensity of the electric field was 18 V / μm.

[0052] Comparative Example 2

[0053] Comparative Example 2 was carried out with reference to Example 1, except that the intensity of the electric field was 52 V / μm.

[0054] Comparative Example 3

[0055] Comparative Example 3 was carried out with reference to Example 1, except that the direction of the electric field was perpendicular to the copper indium thiophosphate nanofilm 10 , and the needle tip 301 was directed toward the copper indium thiophosphate nanofilm 10 .

[0056] Comparative Example 4

[0057] Comparative Example 4 was carried out with reference to Example 1, except that the molar ratio of copper powder, indium block, phosphorus block and sulfur powder was 0.9:1:2:6, and the molecular formula of the prepared copper indium thiophosphate was Cu 0.72 InP2S6, that is, x=0.28.

[0058] Comparative Example 5

[0059] Comparative Example 5 was carried out with reference to Example 1, except that the molar ratio of copper powder, indium block, phosphorus block and sulfur powder was 1.13:1:2:6, and the molecular formula of the copper indium thiophosphate prepared was Cu 0.90 InP2S6, that is, x=0.1.

[0060] Test Example 1

[0061] The test results of the ferroelectric domains and polarized skyrmions in the copper indium thiophosphate iron prepared in Example 1 and Comparative Examples 1 to 5 are shown in Table 1. The surface micromorphology and in-plane and out-of-plane polarization images of the copper indium thiophosphate with polarized skyrmions prepared in Example 1 are shown in Table 1. Figure 3 As shown, Figure 3(A) shows the surface micromorphology of copper indium thiophosphate. Figure 3 (B) shows the out-of-plane amplitude, out-of-plane phase, in-plane amplitude, and in-plane phase before voltage application. Figure 3 Middle (C) shows the out-of-plane amplitude, out-of-plane phase, in-plane amplitude, and in-plane phase after voltage application. Figure 3 Middle (A) and Figure 3 In (C), we can see that the formation of polarized skyrmions is independent of the surface morphology. Figure 3 Middle (B) and Figure 3 As can be seen in (C), the voltage applied by the needle tip 301 breaks the balance between the original electrostatic energy, strain energy and gradient energy in the copper indium thiophosphate nanofilm 10, resulting in the in-plane phase showing a half-bright and half-dark distribution, and the in-plane amplitude showing a two-lobed long strip structure with brighter sides and a dark line in the middle. This is the typical characteristic of polaritons. It can be seen that by applying voltage on the surface of the copper indium thiophosphate nanofilm 10, the ferroelectric domain can be transformed into polaritons.

[0062] Table 1: Test results of copper indium iron thiophosphate prepared in Example 1 and Comparative Examples 1 to 5

[0063]

[0064] Example 2

[0065] Example 2 was carried out with reference to Example 1, except that the intensity of the DC voltage was 35 V / μm.

[0066] Example 3

[0067] Example 3 was carried out with reference to Example 1, except that the intensity of the DC voltage was 29 V / μm.

[0068] Example 4

[0069] Example 4 was carried out with reference to Example 1, except that the thickness of the copper indium thiophosphate nanofilm 10 was 40 nm.

[0070] Example 5

[0071] Example 5 was carried out with reference to Example 1, except that the thickness of the copper indium thiophosphate nanofilm 10 was 80 nm.

[0072] Test Example 2

[0073] With reference to Test Example 1, the test results of ferroelectric domains and polarized skyrmions in the copper indium thiophosphate iron prepared in Examples 2 to 5 are shown in Table 2.

[0074] Table 2: Test results of copper indium iron thiophosphate prepared in Examples 2 to 5

[0075]

[0076] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field, characterized in that: The following steps are involved: Copper indium thiophosphate is prepared by chemical vapor transport, wherein the molecular formula of the copper indium thiophosphate is Cu 1-x InP2S6, 0.28>x≥0.15, the copper indium thiophosphate has ferroelectric domains; preparing the copper indium thiophosphate into a copper indium thiophosphate nanofilm by mechanical stripping technology; placing the copper indium thiophosphate nanofilm on the surface of the substrate by dry transfer technology; Using piezoelectric response force microscopy technology, a voltage is applied to the surface of the copper indium thiophosphate nanofilm through a needle tip to form an electric field, so that the ferroelectric domain is converted into polarized skyrmions, wherein the direction of the electric field is perpendicular to the copper indium thiophosphate nanofilm, and is directed from the copper indium thiophosphate nanofilm to the needle tip, with an intensity of 20V / μm-40V / μm.

2. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to claim 1, characterized in that: The thickness of the copper indium thiophosphate nanofilm is 40nm-80nm.

3. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to claim 2, characterized in that: The voltage is a direct current voltage, the direction of which is perpendicular to the copper indium thiophosphate nanofilm and points from the copper indium thiophosphate nanofilm to the needle tip, and the voltage has a magnitude of 1V-2V.

4. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to any one of claims 1 to 3, characterized in that: The voltage also includes an AC voltage with a magnitude of 0.3V-0.5V.

5. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to any one of claims 1 to 3, characterized in that: In the step of applying an electric field on the surface of the copper indium thiophosphate nanofilm through a needle tip, the scanning frequency is 1.0 Hz-2.0 Hz.

6. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to any one of claims 1 to 3, characterized in that: The substrate is selected from a gold-plated silicon substrate.

7. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to any one of claims 1 to 3, characterized in that: The step of preparing copper indium thiophosphate by chemical vapor transport method includes: growing copper indium thiophosphate under heating and vapor transport medium conditions with a molar ratio of (0.90-1.15):1:2:6 to form copper source, indium source, phosphorus source and sulfur source.

8. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to claim 7, characterized in that: The reaction device for performing chemical vapor transport method includes a source area and a growth area, wherein the heating temperature of the source area is 740°C-760°C, and the heating temperature of the growth area is 690°C-710°C.

9. The method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field according to any one of claims 1 to 3, characterized in that: The polariton skyrmions have a lateral size of 75 nm to 85 nm and a longitudinal size of 180 nm to 220 nm.

10. Use of the method for generating polarized skyrmions by regulating copper indium thiophosphate by electric field as claimed in any one of claims 1 to 9 in memory or logical operations.

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