Spin precession and spin waves in a chiral electron gas: Beyond Larmor's theorem

Article

关键词: DENSITY-FUNCTIONAL THEORY;    LINEAR-RESPONSE;    QUANTUM-WELLS;    RESONANCE;   

DOI  :  10.1103/PhysRevB.96.045301

来源: SCIE

【 摘 要 】

Larmor's theorem holds formagnetic systems that are invariant under spin rotation. In the presence of spin-orbit coupling this invariance is lost and Larmor's theorem is broken: for systems of interacting electrons, this gives rise to a subtle interplay between the spin-orbit coupling acting on individual single-particle states and Coulomb many-body effects. We consider a quasi-two-dimensional, partially spin-polarized electron gas in a semiconductor quantum well in the presence of Rashba and Dresselhaus spin-orbit coupling. Using a linear-response approach based on time-dependent density-functional theory, we calculate the dispersions of spin-flip waves. We obtain analytic results for small wave vectors and up to second order in the Rashba and Dresselhaus coupling strengths alpha and beta. Comparison with experimental data from inelastic light scattering allows us to extract alpha and beta as well as the spin-wave stiffness very accurately. We find significant deviations from the local density approximation for spin-dependent electron systems.

【 授权许可】

Free