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Linear and nonlinear spin current response of anisotropic spin-orbit coupled systems
D Muñoz-Santana1, Jesús A Maytorena2
1Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California, Apartado Postal 360, 22860 Ensenada, Baja California, Mexico.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|September 6, 2023
Summary
This study explores spin current generation in anisotropic materials using spin-orbit (SO) interactions. Researchers found that controlling crystal orientation and SO coupling strengths allows for precise manipulation of linear and second harmonic spin currents for spintronic applications.
Area of Science:
- Condensed Matter Physics
- Spintronics
- Materials Science
Background:
- Spin-orbit (SO) interaction is crucial for generating spin currents in materials.
- Anisotropic systems offer unique properties for controlling spin-dependent phenomena.
- Understanding linear and second harmonic (SH) spin responses is key for advanced spintronic devices.
Purpose of the Study:
- To calculate the linear and SH spin current response in two anisotropic systems with SO interaction.
- To derive general expressions for these response functions applicable to generic two-band Hamiltonians.
- To investigate how material properties and crystal orientation influence spin current generation.
Main Methods:
- Derivation of general expressions for linear and SH spin current response functions.
- Analysis of a 2D electron gas with Rashba and k-linear Dresselhaus SO couplings.
- Investigation of an anisotropic 2D free electron gas with anisotropic Rashba interaction.
Main Results:
- Response spectra characteristics (width, shape, size, frequency shifts) depend on crystal orientation.
- Vanishing linear and SH response tensors are achievable under specific SU(2) symmetry conditions.
- Linear response yields out-of-plane spin currents, while SH response produces in-plane spin currents in anisotropic systems.
Conclusions:
- Precise control over spin current polarization is possible by selecting growth direction and SO strengths.
- Anisotropic systems exhibit distinct linear and SH spin responses, enabling manipulation of spin current generation.
- The findings suggest pathways for realizing the nonlinear spin Hall effect and potential spintronic applications.
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