Logo image
Intersubband spin-density excitations in quantum wells with Rashba spin splitting
Journal article   Open access   Peer reviewed

Intersubband spin-density excitations in quantum wells with Rashba spin splitting

C A Ullrich and M E Flatte
Physical review. B, Vol.66(20), pp.2053051-20530510
11/15/2002
DOI: 10.1103/PhysRevB.66.205305
url
https://arxiv.org/pdf/cond-mat/0206251View
Open Access

Abstract

In inversion-asymmetric semiconductors, spin-orbit coupling induces a k-dependent spin splitting of valence and conduction bands, which is a well-known cause for spin decoherence in bulk and heterostructures. Manipulating nonequilibrium spin coherence in device applications thus requires understanding how valence and conduction band spin splitting affects carrier spin dynamics. This paper studies the relevance of this decoherence mechanism for collective intersubband spin-density excitations (SDE's) in quantum wells. A density-functional formalism for the linear spin-density matrix response is presented that describes SDE's in the conduction band of quantum wells with subbands that may be nonparabolic and spin split due to bulk or structural inversion asymmetry (Rashba effect). As an example, we consider a 40 nm GaAs/Al0.3Ga0.7As quantum well, including Rashba spin splitting of the conduction subbands. We find a coupling and wave-vector-dependent splitting of the longitudinal and transverse SDE's. However, decoherence of the SDE's is not determined by subband spin splitting, due to collective effects arising from dynamical exchange and correlation.
Materials Science Materials Science, Multidisciplinary Physical Sciences Physics Physics, Applied Physics, Condensed Matter Science & Technology Technology

Details

Metrics

Logo image