US-12619007-B2 - Layer, an electronic device, a method of controlling spin transport in the layer

Abstract

A layer including a topological insulator, the layer including: an arrangement of a plurality of patterns on a surface of the layer, each pattern of the plurality of patterns including at least a non-straight elongated portion. An electronic device including the layer including a topological insulator, and further including first and second electrodes on the layer. Further, the first and second electrodes may be configured to provide electrical connection to the layer. A method of controlling spin transport in the layer includes a topological insulator, the method including: applying circularly polarized light on the layer; and driving an electronic component with a photocurrent produced in the layer by the circularly polarized light.

Inventors

• Cesare Soci
• Giorgio ADAMO
• Mustafa EGINLIGIL
• Xinxing SUN
• Harish N.S. KRISHNAMOORTHY
• Nikolay I. Zheludev

Assignees

• NANYANG TECHNOLOGICAL UNIVERSITY

Dates

Publication Date

20260505

Application Date

20210818

Priority Date

20200818

Claims (19)

1. 1 . A layer comprising a topological insulator, the layer comprising: an arrangement of a plurality of patterns on a surface of the layer, each pattern of the plurality of patterns comprising at least a non-straight elongated portion, wherein the pattern is configured to generate a photocurrent which is depending on a helicity of circularly polarized optical excitation.
2. 2 . The layer of claim 1 , wherein the surface is a first main surface extending in first and second directions (D 1 , D 2 ), the first and second directions (D 1 , D 2 ) being perpendicular to each other and to a thickness direction (D 3 ) of the layer.
3. 3 . The layer of claim 2 , wherein each pattern comprises a pattern portion arranged on a second main surface.
4. 4 . The layer of claim 1 , wherein each pattern comprises a surface recess and wherein a thickness of the pattern is a depth of the surface recess.
5. 5 . The layer of claim 1 , wherein each pattern comprises a surface protrusion and wherein a thickness of the pattern is a height of the surface protrusion.
6. 6 . The layer of claim 1 , wherein each pattern comprises a chirality.
7. 7 . The layer of claim 6 , wherein the chirality is present under an oblique angle.
8. 8 . The layer of claim 6 , wherein the chirality is present under a normal angle.
9. 9 . The layer of claim 1 , wherein the pattern comprises or is a square.
10. 10 . The layer of claim 1 , wherein each pattern is configured to resonantly increase optical absorption at a resonant wavelength compared to a pattern free and otherwise identical layer.
11. 11 . The layer of claim 1 , wherein an absorption and/or a photocurrent depends on the helicity of circularly polarized optical excitation at an oblique angle.
12. 12 . The layer of claim 1 , wherein an absorption and/or a photocurrent depends on the helicity of circularly polarized optical excitation at a normal angle.
13. 13 . The layer of claim 1 , wherein the topological insulator comprises transitional metal chalcogenides.
14. 14 . The layer of claim 13 , wherein the topological insulator is Bi 1.5 Sb 0.5 Te 1.8 Se 1.2 .
15. 15 . The layer of claim 1 , wherein the topological insulator comprises Bi, Sb, Te, and Se.
16. 16 . An electronic device comprising the layer comprising the topological insulator of claim 1 , and further comprising first and second electrodes on the layer, wherein the first and second electrodes are configured to provide electrical connection to the layer.
17. 17 . The electronic device of claim 16 , wherein the first and second electrodes are disposed apart from each other on the first main surface of the layer.
18. 18 . The electronic device of claim 16 , wherein the layer is monocrystalline.
19. 19 . A method of controlling spin transport in the layer comprising the topological insulator of claim 1 , the method comprising: applying circularly polarized light on the layer; and driving an electronic component with a photocurrent produced in the layer by the circularly polarized light.

Description

TECHNICAL FIELD An aspect of the disclosure relates to a layer. Another aspect of the disclosure relates to an electronic device. Another aspect of the disclosure relates to a method of controlling spin transport in the layer. Another aspect of the disclosure relates to a use of the layer in an electronic device. BACKGROUND Photosensors are usually made of semiconductor materials and operate on a junction such as a bipolar pn junction. The photosensors may detect properties of light such as intensity, and, with the use of appropriate filters, may be used to discriminate wavelength and polarization of light. For polarization, a linear or circular polarized sensitive sensor may be produced by using a respective polarizer that only allows the desired polarization through. Polarizers add complexity since it requires a mechanical installation in relation to the semiconductor sensing area, increases the bulkiness of the sensor, and costs. Thus, there is need to provide for improved photosensors. SUMMARY An aspect of the disclosure relates to a layer including a topological insulator, the layer including: an arrangement of a plurality of patterns on a surface of the layer, each pattern of the plurality of patterns comprising at least a non-straight elongated portion. The patterns may be formed as a surface relief. According to various embodiments, the surface may be a first main surface extending in first and second directions, the first and second directions being perpendicular to each other and to a thickness direction of the layer. According to various embodiments, the patterns may include a pattern portion arranged on a second main surface. According to various embodiments, each pattern may include a surface recess. Further, a thickness of the pattern may be a depth of the surface recess. According to various embodiments, each pattern may include a surface protrusion. Further, a thickness of the pattern may be a height of the surface protrusion. According to various embodiments, each pattern may include uniform thickness along the non-straight elongated portion or along an elongation of the pattern. According to various embodiments, each pattern may include varying thickness along the non-straight elongated portion or along an elongation of the pattern. According to various embodiments, each pattern may include a chirality. According to various embodiments, the chirality may be present under an oblique angle. According to various embodiments, the chirality may be present under a normal angle. According to various embodiments, the arrangement may form a lattice, for example, a square lattice. According to various embodiments, the pattern may include or be an L-shape. According to various embodiments, the pattern may include or be a square. According to various embodiments, each pattern may be configured to resonantly increase optical absorption at a resonant wavelength compared to a pattern free and otherwise identical layer. According to various embodiments, the pattern may be configured to generate a photocurrent which may be depending on a helicity of circularly polarized optical excitation. According to some embodiments, an absorption and/or a photocurrent of the layer depends on the helicity of circularly polarized optical excitation at oblique angles. According to some embodiments, an absorption and/or a photocurrent depends on the helicity of circularly polarized optical excitation at normal angle. According to various embodiments, the topological insulator may include transitional metal chalcogenides. According to various embodiments, the topological insulator may include Bismuth (Bi), Antimony (Sb), Tellurium (Te), and Selenium (Se). According to various embodiments, the topological insulator may be Bi1.5Sb0.5Te1.8Se1.2 (BSTS). An aspect of the disclosure relates to an electronic device including a layer including a topological insulator, and further including first and second electrodes on the layer. Further, the first and second electrodes may be configured to provide electrical connection to the layer. According to various embodiments, the first and second electrodes may be disposed apart from each other on the first main surface of the layer. According to various embodiments, the layer may be monocrystalline. An aspect of the disclosure relates to a method of controlling spin transport in the layer including a topological insulator, the method including: applying circularly polarized light on the layer; and driving an electronic component with a photocurrent produced in the layer by the circularly polarized light. An aspect of the disclosure relates to a topological insulator, as described above, in an electronic device. The electronic device may be selected from: a polarization sensitive photodetector; a spin polarized photodetector; a device for measuring molecular chirality; a quantum opto-spintronic device for transferring of polarization and entanglement from photons to electron spins. BRIEF D