Dynamical polarization of nuclear spins by acceptor-bound holes in a zinc blende semiconductor

TL;DR

This paper develops a theory describing how acceptor-bound holes in zinc blende semiconductors dynamically polarize nuclear spins, revealing anisotropic hyperfine interactions and spatially inhomogeneous nuclear spin polarization.

Contribution

It introduces a comprehensive model accounting for the complex spin structure of acceptor-bound holes and their role in nuclear spin polarization in zinc blende semiconductors.

Findings

Hyperfine interaction becomes anisotropic and coordinate-dependent.

Nuclear spin polarization depends on the angle between hole angular momentum and nuclear position.

Inhomogeneous nuclear polarization causes non-uniform spin splitting detectable by spectroscopy.

Abstract

The ground state of an acceptor-bound hole in a zinc-blende semiconductor is formed by four eigenstates of the total angular momentum, which is a vector sum of spin and orbital moment of the hole. As a result, the hyperfine interaction of the hole with lattice nuclei becomes anisotropic and coordinate-dependent. We develop a theory of dynamic polarization of nuclear spins by the acceptor-bound hole, giving full account for its complex spin structure. The rate of hole-nuclear flip-flop transitions is shown to depend on the angle between the total angular momentum of the hole and the position vector of the nucleus with respect to the acceptor center. The resulted spatially inhomogeneous spin polarization of nuclei gives rise to non-equidistant spin splitting of the hole, which can be detected by methods of optical or microwave spectroscopy.