Electrical and Optical Devices Incorporating Topological Materials Including Topological Insulators

• US 20120138887A1
• Filed: 12/06/2011
• Published: 06/07/2012
• Est. Priority Date: 12/07/2010
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Zhang, Shoucheng, Zhang, Xiao
• Granted Patent: US 9,024,415 B2
• Time in Patent Office: Days
• US Class Current: 257/9
• CPC Class Codes: H01F 1/0009 Antiferromagnetic materials, i.e. materials exhibiting a Néel transition temperature H01F1/0036 takes precedence
• CPC Class Codes: H01F 1/401 diluted
• CPC Class Codes: H01L 29/785 having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 31/08 in which radiation controls flow of current through the device, e.g. photoresistors
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

An electrical device includes a current transport layer formed using a layer of a topological material selected from the group of a topological insulator, a quantum anomalous hall (QAH) insulator, a topological insulator variant, and a topological magnetic insulator. In one embodiment, the current transport layer forms a conductive wire on an integrated circuit where the conductive wire includes two spatially separated edge channels, each edge channel carrying charge carriers propagating in one direction only. In other embodiments, an optical device includes an optical layer formed using a layer of the topological material. The optical layer can be a light absorbing layer, a light emitting layer, a light transport layer, or a light modulation layer.

Claims

1. An electrical device, comprising:

a current transport layer formed using a layer of a topological material, the topological material being selected from the group of a topological insulator, a quantum anomalous hall (QAH) insulator, a topological insulator variant, and a topological magnetic insulator, wherein the topological insulator and the QAH insulator both have an insulating energy band gap in the bulk and conducting edge or surface states, the topological insulator variant is formed from a topological insulator material, and the topological magnetic insulator comprises an antiferromagnetic insulator; and

at least one electrode in electrical contact with the current transport layer.

2. The electrical device of claim 1, wherein the layer of topological material comprises a two-dimensional (2D) or three-dimensional (3D) topological insulator layer with an insulating energy band gap in the bulk and conducting edge or surface states, respectively, protected by time-reversal symmetry.

3. The electrical device of claim 2, wherein the layer of topological material comprises a two-dimensional (2D) or three-dimensional (3D) topological insulator variant layer, the topological insulator variant layer being formed from a 2D or 3D topological insulator layer by thickness control, by magnetic doping, or by applying an electrical potential to the topological insulator layer.

4. The electrical device of claim 3, wherein the 2D topological insulator variant layer is formed by varying the thickness of a 2D topological insulator layer, wherein when the thickness of the 2D topological insulator layer is varied, the 2D topological insulator variant layer becomes a topological insulator or a trivial insulator.

5. The electrical device of claim 3, wherein the 2D topological insulator variant layer is formed from a 2D topological insulator layer having a thickness close to a critical thickness, the 2D topological insulator variant layer becoming a conductor layer.

6. The electrical device of claim 3, wherein the 3D topological insulator variant layer is formed by varying the thickness of a 3D topological insulator layer, wherein when the thickness of the 3D topological insulator layer is reduced, the surface states of the topological insulator layer become gapped or have an appreciable energy band gap and the 3D topological insulator variant layer becomes a 2D insulator.

7. The electrical device of claim 3, wherein the topological insulator variant layer is formed by magnetic doping of a 2D or 3D topological insulator layer, wherein the magnetic doping breaks the time-reversal symmetry of the edge or surface states, respectively.

8. The electrical device of claim 7, wherein the topological insulator variant layer is formed by surface magnetic doping of a topological insulator layer.

9. The electrical device of claim 7, wherein the topological insulator variant layer is formed by magnetic doping of the surface and the bulk of a topological insulator layer.

10. The electrical device of claim 3, wherein the topological insulator variant layer is formed by the application of an electrical potential to a topological insulator layer.

11. The electrical device of claim 3, wherein the layer of topological material comprises a 3D topological insulator variant layer formed by the application of an electrical potential to a 3D topological insulator layer, wherein upon the application of the electrical potential to the 3D topological insulator variant layer, the surface states of the 3D topological insulator variant layer become a topological insulator or a trivial insulator having a gapped energy band gap or appreciable energy band gap.

12. The electrical device of claim 6, wherein the layer of topological material comprises a 3D topological insulator variant layer formed by the application of an electrical potential to a 3D topological insulator variant layer with reduced thickness, wherein the surface states of the 3D topological insulator variant layer become a topological insulator or a trivial insulator having a gapped energy band gap or appreciable energy band gap.

13. The electrical device of claim 2, wherein the topological insulator layer is formed using a material selected from the group of HgTe, Bi_xSb_1-x, Sb₂Te₃, Bi₂Te₃, Bi₂Se₃, TlBiTe₂, TlBiSe₂, selected ternary Heusler compounds, selected chalcogenides, including Ge₁Bi₄Te₇, Ge₂Bi₂Te₅, and Ge₁Bi₂Te₄, and topological insulators with strong interaction such as AmN, PuTe.

14. The electrical device of claim 1, wherein the quantum anomalous hall insulator layer has an insulating energy band gap in the bulk and gapless chiral edge states protected by the first Chern number.

15. The electrical device of claim 1, wherein the topological magnetic insulator layer comprises a three-dimensional topological magnetic insulator layer wherein the antiferromagnetic order breaks the time-reversal symmetry of an insulator layer spontaneously and the magnetic fluctuations of the topological magnetic insulator layer are coupled linearly to an axion field.

16. The electrical device of claim 3, wherein the current transport layer forms a conductive wire on an integrated circuit being configured as an interconnect between a signal source and a first terminal of a load, wherein the conductive wire comprises two spatially separated edge channels, each edge channel carrying charge carriers propagating in one direction only, the two edge channels carrying charge carriers propagating in opposite directions.

17. The electrical device of claim 16, wherein the layer of the topological material forming the conductive wire comprises a two-dimensional quantum anomalous hall insulator layer with an insulating energy band gap in the bulk and gapless chiral edge states protected by the first Chern number, the chiral edge state being an edge state that carries current uni-directionally, the two-dimensional quantum anomalous hall insulator layer being formed a first distance away from a ground plate or a second wire, the load having a second terminal coupled to the ground plate or to the second wire.

18. The electrical device of claim 16, wherein the layer of the topological material comprises a three-dimensional topological insulator variant layer with magnetic doping, the three-dimensional topological insulator variant layer being a material with an insulating energy band gap in the bulk and the magnetic doping of the topological insulator variant layer breaking the time-reversal symmetry of the surface states,

wherein the three-dimensional topological insulator variant layer with magnetic doping includes a first region of a first magnetic domain and a second region of a second magnetic domain, the second magnetic domain being opposite to the first magnetic domain, the first and second regions being formed by magnetic doping of the topological insulator variant layer, and wherein the conductive wire comprises an axion string interconnect formed at the boundary between the first region and the second region.

19. The interconnect device of claim 18, wherein the axion string interconnect comprises a programmable interconnect where programming of the axion string interconnect is realized by changing the polarities of the first and second magnetic domains.

20. The electrical device of claim 3, further comprising:

a substrate on which the layer of topological material is formed;

a gate dielectric layer formed over at least a portion of the layer of topological material;

a gate electrode formed over the gate dielectric layer;

a source terminal formed on a side of the gate dielectric layer; and

a drain terminal formed on the other side of the gate dielectric layer,

wherein the layer of topological material under the gate dielectric layer forms a channel region of a transistor formed by the gate electrode, the source and drain terminals, the layer of topological material comprising a topological insulator layer or a topological insulator variant layer with thickness control.

21. The electrical device of claim 20, wherein a constant voltage is applied to the gate electrode and the source electrode of the transistor and a constant current is applied to the source and drain electrodes of the transistor, a plasma is generated in the channel region of the transistor, the plasma emitting radiation.

22. The electrical device of claim 20, wherein the layer of topological material is selected from the group of a three-dimensional topological insulator layer, a two-dimensional topological insulator layer having a thickness close to a critical thickness, and a three-dimensional topological insulator layer having a thickness close to a critical thickness of a 2D insulator formed therefrom.

23. The electrical device of claim 3, further comprising:

a first electrode in electrical contact with the current transport layer; and

a second electrode in electrical contact with the current transport layer, the second electrode being formed spaced apart from the first electrode,

wherein when an input signal having a first frequency is applied between the first and second electrodes, an output signal having a second frequency being multiples of the first frequency is generated in the surface of the layer of topological material.

24. The electrical device of claim 3, further comprising:

a first electrode in electrical contact with the current transport layer; and

a second electrode in electrical contact with the current transport layer, the second electrode being formed spaced apart from the first electrode,

wherein when a light impinges on the layer of the topological material, a current or a voltage indicative of the amount of incident light is generated in the surface of the layer of the topological material.

25. The electrical device of claim 24, wherein the layer of the topological material comprises a three-dimensional topological insulator variant layer with thickness control to cause the surface of the 3D topological insulator variant layer to become a gaped energy band semiconductor layer, where the band gap is modulated by applying an electrical potential to the 3D topological insulator variant layer, the band gap of the topological insulator variant layer being modulated to control light detection.

26. The electrical device of claim 24, further comprising a voltage source applying a voltage between the first and second electrodes.

27. The electrical device of claim 3, wherein the layer of topological material comprises a three-dimensional topological insulator variant layer with magnetic doping, the three-dimensional topological insulator variant layer being a material with an insulating energy band gap in the bulk and conducting edge states, the magnetic doping of the topological insulator variant layer breaking the time-reversal symmetry of the edge states, the electrical device further comprising:

a magnetic memory device layer formed adjacent to the layer of the topological material,

wherein the electrical device comprises a magnetic monopole memory device and when an electric charge is applied in a vicinity of the magnetic memory device layer, a magnetic field is generated in the magnetic memory device layer through an imaging magnetic monopole of the electric charge formed in the layer of the topological material.

28. The electrical device of claim 1, wherein the current transport layer comprises a transparent electrode.

29. The electrical device of claim 1, wherein the current transport layer forms a gain layer of a laser.

30. An optical device, comprising:

an optical layer formed using a layer of a topological material, the topological material being selected from the group of a topological insulator, a quantum anomalous hall (QAH) insulator, a topological insulator variant, and a topological magnetic insulator, wherein the topological insulator and the QAH insulator both have an insulating energy band gap in the bulk and conducting edge or surface states, the topological insulator variant is formed from a topological insulator material, and the topological magnetic insulator comprises an antiferromagnetic insulator,

wherein the optical layer comprises one of a light absorbing layer, a light emitting layer, a light transport layer, or a light modulation layer.

31. The optical device of claim 30, wherein the layer of topological material comprises a two-dimensional or three-dimensional topological insulator layer with an insulating energy band gap in the bulk and conducting edge or surface states, respectively, protected by time-reversal symmetry.

32. The optical device of claim 31, wherein the layer of topological material comprises a two-dimensional or three-dimensional topological insulator variant layer, the topological insulator variant layer being formed from a topological insulator layer by thickness control, by magnetic doping, or by applying an electrical potential to the topological insulator layer.

33. The optical device of claim 30, wherein the layer of topological material comprises a two-dimensional quantum anomalous hall insulator layer with an insulating energy band gap in the bulk and gapless chiral edge states protected by the first Chern number.

34. The optical device of claim 30, wherein the layer of topological material comprises a three-dimensional topological magnetic insulator layer wherein the antiferromagnetic order breaks the time-reversal symmetry of a topological insulator layer spontaneously and the magnetic fluctuations of the topological magnetic insulator layer are coupled linearly to an axion field.

35. The optical device of claim 34, wherein the optical device comprises an amplitude optical modulator, the optical layer of the amplitude optical modulator being a topological magnetic insulator layer operating based on axionic polariton being a coupled mode of light and the axionic mode of the topological magnetic insulator, the topological magnetic insulator layer transmitting incident light when no external magnetic field is applied and the topological magnetic insulator layer reflecting at least a part of the incident light when an external magnetic field is applied parallel to an electric field of the light in the layer.