Delgado Acosta, Fernando, Fernández-Rossier, Joaquín
Enhanced lifetimes of spin chains coupled to chiral edge states
New Journal of Physics. 2019, 21: 043008. doi:10.1088/1367-2630/ab116b
URI: http://hdl.handle.net/10045/93731
DOI: 10.1088/1367-2630/ab116b
ISSN: 1367-2630
Abstract: 
We consider spin relaxation of finite-size spin chains exchanged coupled with a one-dimensional (1D) electron gas at the edge of a quantum spin Hall (QSH) insulator. Spin lifetimes can be enhanced due to two independent mechanisms. First, the suppression of spin-flip forward scattering inherent in the spin momentum locking of the QSH edges. Second, the reduction of spin-flip backward scattering due to destructive interference of the quasiparticle exchange, modulated by k F d, where d is the inter-spin distance and k F is the Fermi wavenumber of the electron gas. We show that the spin lifetime of the S = 1/2 ground state of odd-numbered chains of antiferromagnetically coupled S = 1/2 spins can be increased more than 4 orders of magnitude by properly tuning the product k F d and the spin size N, in strong contrast with the 1D case. Possible physical realizations together with some potential issues are also discussed.
Keywords:Spin Hall, Decoherence, Relaxation, Adatoms, Kondo
IOP Publishing
info:eu-repo/semantics/article