Ballistic spin resonance in multisubband quantum wires

• Published in: arXiv.org
• Main Authors: Hachiya, Marco O, Usaj, Gonzalo, Egues, J Carlos
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 31.03.2014
• Subjects: Couplings; Elastic scattering; Larmor precession; Magnetic fields; Orbital resonances (celestial mechanics); Physics - Mesoscale and Nanoscale Physics; Quantum mechanics; Quantum wires; Relaxation time; Resonance scattering; Spin resonance; Spin-orbit interactions; Time dependence
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1310.3707

Ballistic spin resonance was experimentally observed in a quasi-one-dimensional wire by Frolov et al. [Nature (London) 458, 868 (2009)]. The spin resonance was generated by a combination of an external static magnetic field and the oscillating effective spin-orbit magnetic field due to periodic bouncings of the electrons off the boundaries of a narrow channel. An increase of the D'yakonov-Perel spin relaxation rate was observed when the frequency of the spin-orbit field matched that of the Larmor precession frequency around the external magnetic field. Here we develop a model to account for the D'yakonov-Perel mechanism in multisubband quantum wires with both the Rashba and Dresselhaus spin-orbit interactions. Considering elastic spin-conserving impurity scatterings in the time-evolution operator (Heisenberg representation), we extract the spin relaxation time by evaluating the time-dependent average of the spin operators. The magnetic field dependence of the nonlocal voltage, which is related to the spin relaxation time behavior, shows a wide plateau, in agreement with the experimental observation. This plateau arises due to injection in higher subbands and small-angle scattering. In this quantum mechanical approach, the spin resonance occurs near the spin-orbit induced energy anticrossings of the quantum wire subbands with opposite spins. We also predict anomalous dips in the spin relaxation time as a function of the magnetic field in systems with strong spin-orbit couplings.