Substrate effects on spin relaxation in two-dimensional Dirac materials with strong spin-orbit coupling  

作　　者：Junqing Xu Yuan Ping 

机构地区：[1]Department of Chemistry and Biochemistry,University of California,Santa Cruz,CA 95064,USA

出　　处：《npj Computational Materials》2023年第1期1880-1889,共10页计算材料学（英文）

基　　金：This work is supported by the Air Force Office of Scientific Research under AFOSR Award No.FA9550-21-1-0087;This research used resources of the Center for Functional Nanomaterials,which is a US DOE Office of Science Facility,and the Scientific Data and Computing center,a component of the Computational Science Initiative,at Brookhaven National Laboratory under Contract No.DE-SC0012704;the lux supercomputer at UC Santa Cruz,funded by NSF MRI grant AST 1828315;the National Energy Research Scientific Computing Center(NERSC)a U.S.Department of Energy Office of Science User Facility operated under Contract No.DE-AC02-05CH11231;the Extreme Science and Engineering Discovery Environment(XSEDE)which is supported by National Science Foundation Grant No.ACI-154856243.

摘　　要：Understanding substrate effects on spin dynamics and relaxation is of key importance for spin-based information technologies.However, the key factors that determine such effects, in particular for materials with strong spin-orbit coupling (SOC), have notbeen well understood. Here we performed first-principles real-time density-matrix dynamics simulations with SOC and the electron-phonon and electron-impurity scattering for spin lifetimes (τ_(s)) of supported/free-standing germanene, a prototypical strong SOC 2DDirac material. We show that the effects of different substrates on τ_(s) can surprisingly differ by two orders of magnitude. We find thatsubstrate effects on τs are closely related to substrate-induced modifications of the SOC-field anisotropy, which changes the spin-flip scattering matrix elements. We propose a new electronic quantity, named spin-flip angle θ↑↓, to characterize spin relaxationthrough intervalley spin-flip scattering. We find that T_(s)^(-1) is approximately proportional to the averaged value of sin^(2)( θ↑↓/2 ) , whichserves as a guiding parameter of controlling spin relaxation.

关 键 词：MATERIAL RELAXATION COUPLING 

分 类 号：TB33[一般工业技术—材料科学与工程]