Pure spin current and perfect valley filter by designed separation of the chiral states in two-dimensional honeycomb lattices

AbstractRecent discovered two-dimensional (2D) antiferromagnetic (AFM) van der Waals quantum materials have attracted increasing interest due to the emergent exotic physical phenomena. The spintronic properties utilizing the intrinsic AFM state in 2D antiferromagnets, however, have been rarely found. Here we show that the spin photogalvanic effect (SPGE), which has been predicted in three-dimensional (3D) antiferromagnets, can intrinsically emerge in 2D antiferromagnets for promising spintronic applications. Based on the symmetry analysis of possible AFM orders in the honeycomb lattice, we conclude suitable 2D AFM candidate materials for realizing the SPGE. We choose two experimentally synthesized 2D collinear AFM materials, monolayer MnPS3, and bilayer CrCl3, as representative materials to perform first-principles calculations, and find that they support sizable SPGE. The SPGE in collinear 2D AFM materials can be utilized to generate pure spin current in a contactless and ultra-fast way.

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Two-dimensional centrosymmetrical antiferromagnets for spin photogalvanic devices

npj Quantum Information ◽

10.1038/s41534-021-00365-7 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Peng Jiang ◽

Xixi Tao ◽

Hua Hao ◽

Yushen Liu ◽

Xiaohong Zheng ◽

...

Keyword(s):

Spin Polarization ◽

Electric Fields ◽

Spin Current ◽

Spin Splitting ◽

Antiferromagnetic Coupling ◽

Pure Spin ◽

Two Dimensional ◽

Photoelectric Device ◽

Current Generation ◽

Low Dimensional

AbstractSpin-dependent photogalvanic effect (PGE) in low-dimensional magnetic systems has recently attracted intensive attention. Based on first-principle transport calculations and symmetry analyses, we propose a robust scheme to generate pure spin current by PGE in centrosymmetric materials with spin polarization antisymmetry. As a demonstration, the idea is successfully applied to a photoelectric device constructed with a zigzag graphene nanoribbon (ZGNR), which has intrinsic antiferromagnetic coupling between the two edges and spin degenerate band structure. It suggests that spin splitting is not a prerequisite for pure spin current generation. More interestingly, by further introducing external transverse electric fields to the two leads to lift the spin degeneracy, the device may behave multifunctionally, capable of producing fully spin-polarized current or pure spin current, depending on whether the fields in the two leads are parallel or antiparallel. Very importantly, our scheme of pure spin current generation with PGE is not limited to ZGNR and can be extended to other two-dimensional (2D) centrosymmetric magnetic materials with spin polarization antisymmetry, suggesting a promising category of 2D platforms for PGE-based pure spin current generation.

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Pure spin current generated by reflection at a normal metal/two-dimensional electron gas interface

Physical Review B ◽

10.1103/physrevb.81.075312 ◽

2010 ◽

Vol 81 (7) ◽

Cited By ~ 6

Author(s):

Jacob Linder ◽

Takehito Yokoyama ◽

Asle Sudbø

Keyword(s):

Electron Gas ◽

Spin Current ◽

Normal Metal ◽

Pure Spin ◽

Two Dimensional ◽

Dimensional Electron ◽

Two Dimensional Electron Gas ◽

Dimensional Electron Gas

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Pure spin photocurrent in non-centrosymmetric crystals: bulk spin photovoltaic effect

Nature Communications ◽

10.1038/s41467-021-24541-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Haowei Xu ◽

Hua Wang ◽

Jian Zhou ◽

Ju Li

Keyword(s):

Mirror Symmetry ◽

Photovoltaic Effect ◽

Transition Metal Dichalcogenides ◽

Spin Current ◽

Pure Spin ◽

Light Illumination ◽

Metal Dichalcogenides ◽

Critical Components ◽

Topological Crystalline Insulator

AbstractSpin current generators are critical components for spintronics-based information processing. In this work, we theoretically and computationally investigate the bulk spin photovoltaic (BSPV) effect for creating DC spin current under light illumination. The only requirement for BSPV is inversion symmetry breaking, thus it applies to a broad range of materials and can be readily integrated with existing semiconductor technologies. The BSPV effect is a cousin of the bulk photovoltaic (BPV) effect, whereby a DC charge current is generated under light. Thanks to the different selection rules on spin and charge currents, a pure spin current can be realized if the system possesses mirror symmetry or inversion-mirror symmetry. The mechanism of BSPV and the role of the electronic relaxation time $$\tau$$ τ are also elucidated. We apply our theory to several distinct materials, including monolayer transition metal dichalcogenides, anti-ferromagnetic bilayer MnBi2Te4, and the surface of topological crystalline insulator cubic SnTe.

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