Dissipation-relaxation dynamics of a spin- 12 particle with a Rashba-type spin-orbit coupling in an ohmic heat bath

Tomohiro Hata, Eiji Nakano, Kei Iida, Hiroyuki Tajima, Junichi Takahashi

研究成果: Article査読

抄録

Spin-orbit coupling (SOC), which is inherent in a Dirac particle that moves under the influence of electromagnetic fields, manifests itself in a variety of physical systems, including nonrelativistic ones. For instance, it plays an essential role in spintronics developed in the past few decades, particularly by controlling spin current generation and relaxation. In the present work, by using an extended Caldeira-Leggett model, we elucidate how the interplay between spin relaxation and momentum dissipation of an open system of a single spin-12 particle with Rashba-type SOC is induced by the interactions with a spinless, three-dimensional environment. Staring from the path-integral formulation for the reduced density matrix of the system, we have derived a set of coupled nonlinear equations that consists of a quasiclassical Langevin equation for the momentum with a frictional term and a spin precession equation. The spin precesses around the effective magnetic field generated by both the SOC and the frictional term. It is found from analytical and numerical solutions to these equations that a spin torque effect included in the effective magnetic field causes a spin relaxation and that the spin and momentum orientations after a long time evolution are largely controlled by the Rashba coupling strength. Such a spin relaxation mechanism is qualitatively different from, e.g., the one encountered in semiconductors in which essentially no momentum dissipation occurs due to the Pauli blocking.

本文言語English
論文番号144424
ジャーナルPhysical Review B
104
14
DOI
出版ステータスPublished - 2021 10月 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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