Theory of electric dipole spin resonance in quantum dots: Mean field theory with Gaussian fluctuations and beyond

TL;DR

This paper develops a unified microscopic mean field theory for electric dipole spin resonance (EDSR) in quantum dots, explaining different mechanisms and their distinct time-dependent behaviors, and extends to include nuclear-spin correlations.

Contribution

It introduces a comprehensive mean field framework for EDSR in quantum dots, incorporating multiple mechanisms and higher nuclear-spin correlations beyond previous models.

Findings

Different EDSR mechanisms exhibit distinct time behaviors, from Rabi oscillations to monotonic growth.

The theory justifies using macroscopic nuclear polarization in EDSR modeling.

Higher nuclear-spin correlators significantly influence long-term EDSR dynamics.

Abstract

Very recently, the electric dipole spin resonance (EDSR) of single electrons in quantum dots was discovered by three independent experimental groups. Remarkably, these observations revealed three different mechanisms of EDSR: coupling of electron spin to its momentum (spin-orbit), to the operator of its position (inhomogeneous Zeeman coupling), and to the hyperfine Overhauser field of nuclear spins. In this paper, I present a unified microscopic theory of these resonances in quantum dots. A mean field theory, derived for all three mechanisms and based on retaining only two-spin correlators, justifies applying macroscopic description of nuclear polarization to the EDSR theory. In the framework of the mean field theory, a fundamental difference in the time dependence of EDSR inherent of these mechanisms is revealed; it changes from the Rabi-type oscillations to a nearly monotonic growth. The theory provides a regular procedure to account for the higher nuclear-spin correlators that become of importance for a wider time span and can change the asymptotic behavior of EDSR. It also allows revealing the effect of electron spin dynamics on the effective coupling between nuclear spins.