Quantum rings with Rashba spin-orbit coupling: A path-integral approach

Abstract

We employ a path-integral real-time approach to compute the dc conductance and spin polarization for electrons transported across a ballistic quantum ring with Rashba spin-orbit interaction. We use a piecewise semiclassical approximation for the particle orbital motion and solve the spin dynamics exactly by accounting for both Zeeman coupling and spin-orbit interaction at the same time. Within our approach, we are able to study how the interplay between Berry phase, Aharonov Casher phase, Zeeman interaction, and weak localization corrections influences the quantum interference in the conductance within a wide range of externally applied fields. Our results are helpful in interpreting recent measurements of interferometric rings.

Aharonov-Casher and spin Hall effects in mesoscopic ring structures with strong spin-orbit interaction

“…When the carrier density is chosen so that the Fermi energy is not very close to a value of the eigenvalues of the ring, then the electron gets backscattered once and as it travels around the ring the path taken and the same path but time reversed are interfering with each other, similar to weak localization corrections to the conductance. 35 The Q e = 0 result is also in agreement with the results obtained by Lucignano et al 36 for AB rings where once they FIG. 3.…”

Current-conserving Aharonov-Bohm interferometry with arbitrary spin interactions

“…The previous studies considering the effect of both the Rashba SOC and the Zeeman splitting have dealt with this situation by using various methods: the transfer-matrix method accompanied with wave-function matching, 5,8,10 the perturbative approach, 14 the path-integral approach, 17 and numerical calculations based on tight-binding models. 13,16,22 Among them, it is only the numerical methods 13,16,22 that fulfill the charge-current conservation.…”

“…In the presence of external magnetic fields, the Zeeman splitting is operative together with the SOC and its effect should be taken into account. 5,8,10,14,17 The general framework for the theoretical studies of the mesoscopic transport relies on the Landauer approach, 34 in which the tunneling between conduction modes in electrodes and mesoscopic systems can be described in terms of a scattering matrix. The scattering matrix relates the amplitudes and phases of the outgoing and incoming modes at a coherent scatterer.…”

Time-resolved quantum spin transport through an Aharonov–Casher ring

“…How to control and engineer the spin degree of freedom at the mesoscopic scale is a crucial step for spintronic devices [1][2][3][4][5][6][7]. It has been demonstrated that spins of conduction electrons can be manipulated by external gating voltage through the Rashba spin-orbit interaction (RSOI) [8][9][10][11][12][13][14][15]. Such the electric field-tunable RSOI can be achieved as well on the Aharonov-Casher (AC) effect [16] in mesoscopic ring structures [17][18][19].…”