Driven dynamics of a quantum dot electron spin coupled to a bath of higher-spin nuclei

摘要

The interplay of optical driving and hyperfine interactions between an electron confined in a quantum dot and its surrounding nuclear spin environment produces a range of interesting physics stemming from the creation of dynamic nuclear polarization. In this paper, we go beyond the ubiquitous spin-1/2 approximation for nuclear spins and present a comprehensive theoretical framework for an optically driven electron spin in a self-assembled quantum dot coupled to a nuclear spin bath of arbitrary spin. Using a dynamical mean-field approach, we compute the nuclear spin polarization distribution with and without the quadrupolar coupling. We find that while hyperfine interactions drive dynamic nuclear polarization in such a way that the electron spin precession becomes synchronized with the driving, quadrupolar couplings counteract this phenomenon. The tension between these mechanisms is imprinted on the steady-state electron spin evolution, providing a way to measure the importance of quadrupolar interactions in a quantum dot. Our results show that higher-spin effects such as quadrupolar interactions can have a significant impact on the generation of dynamic nuclear polarization and how it influences the electron spin evolution.