Microscopic linear response theory of spin relaxation and relativistic transport phenomena in graphene

TY - JOUR

T1 - Microscopic linear response theory of spin relaxation and relativistic transport phenomena in graphene

AU - Offidani, Manuel

AU - Raimondi, Roberto

AU - Ferreira, Aires

N1 - ©2018 by the authors.

PY - 2018/6

Y1 - 2018/6

N2 - We present a unified theoretical framework for the study of spin dynamics and relativistic transport phenomena in disordered two-dimensional Dirac systems with pseudospin-spin coupling. The formalism is applied to the paradigmatic case of graphene with uniform Bychkov-Rashba interaction and shown to capture spin relaxation processes and associated charge-to-spin interconversion phenomena in response to generic external perturbations, including spin density fluctuations and electric fields. A controlled diagrammatic evaluation of the generalized spin susceptibility in the diffusive regime of weak spin-orbit interaction allows us to show that the spin and momentum lifetimes satisfy the standard Dyakonov-Perel relation for both weak (Gaussian) and resonant (unitary) nonmagnetic disorder. Finally, we demonstrate that the spin relaxation rate can be derived in the zero-frequency limit by exploiting the SU(2) covariant conservation laws for the spin observables. Our results set the stage for a fully quantum-mechanical description of spin relaxation in both pristine graphene samples with weak spin-orbit fields and in graphene heterostructures with enhanced spin-orbital effects currently attracting much attention.

AB - We present a unified theoretical framework for the study of spin dynamics and relativistic transport phenomena in disordered two-dimensional Dirac systems with pseudospin-spin coupling. The formalism is applied to the paradigmatic case of graphene with uniform Bychkov-Rashba interaction and shown to capture spin relaxation processes and associated charge-to-spin interconversion phenomena in response to generic external perturbations, including spin density fluctuations and electric fields. A controlled diagrammatic evaluation of the generalized spin susceptibility in the diffusive regime of weak spin-orbit interaction allows us to show that the spin and momentum lifetimes satisfy the standard Dyakonov-Perel relation for both weak (Gaussian) and resonant (unitary) nonmagnetic disorder. Finally, we demonstrate that the spin relaxation rate can be derived in the zero-frequency limit by exploiting the SU(2) covariant conservation laws for the spin observables. Our results set the stage for a fully quantum-mechanical description of spin relaxation in both pristine graphene samples with weak spin-orbit fields and in graphene heterostructures with enhanced spin-orbital effects currently attracting much attention.

KW - 2DEGs

KW - Diagrammatic theory

KW - Graphene

KW - Spin relaxation

KW - Spin-Galvanic effect

KW - Spin-orbit coupling

KW - Spintronics

UR - http://www.scopus.com/inward/record.url?scp=85058279788&partnerID=8YFLogxK

U2 - 10.3390/condmat3020018

DO - 10.3390/condmat3020018

M3 - Article

AN - SCOPUS:85058279788

SN - 2410-3896

VL - 3

SP - 1

EP - 20

JO - Condensed Matter

JF - Condensed Matter

IS - 2

M1 - 18

ER -