Electrical spin manipulation in double SrTiO$_3$/LaAlO$_3$ quantum dots
Abstract
The spin dynamics in two electron double quantum dots embedded in two dimensional electron gas at the interface between SrTiO and LaAlO is studied by an exact numerical solution of the time-dependent Schr\"odinger equation, in the context of the electric dipole spin resonance experiment. Based on the three band model of -electrons localized at Ti ions on the square lattice we analyze in details the singlet-triplet transition induced by the AC electric field, in the magnetic field range close to the avoided crossing which appears as a result of the spin-orbit coupling. Our calculations show that for symmetric double quantum dots the single photon spin-flip transitions is prohibited due to the parity symmetry and the transition can occur only by the higher order two-photon processes. For a weakly asymmetric system, when the first order singlet-triplet transitions are released due to the parity symmetry breaking, the spin-flip transition has a character of the Rabi oscillations for a low electric field amplitude. As the amplitude is increased the frequency of the transition is blueshifted (redshifted) for the magnetic field below (above) the single-triplet avoided crossing. Interestingly, for a sufficiently high magnetic field and high AC field amplitude the electric field drives the system across the avoided crossing inducing the spin-flip by the Landau-Zener-Stueckelberg-Majorana transitions with 100\% spin flip probability for a slow sweep. Finally, the optimization of the geometrical parameters of the system with respect to the time of spin-flip of its fidelity is also presented.
Cite
@article{arxiv.2404.14272,
title = {Electrical spin manipulation in double SrTiO$_3$/LaAlO$_3$ quantum dots},
author = {B. Szafran and M. Zegrodnik and M. P. Nowak and R. Citro and P. Wojcik},
journal= {arXiv preprint arXiv:2404.14272},
year = {2024}
}