Spin relaxation of localized electrons in n-type semiconductors

TL;DR

This paper theoretically analyzes the spin relaxation mechanisms of localized electrons in n-type semiconductors, comparing them with experimental data, and discusses potential optical cooling of the spin system.

Contribution

It provides a comprehensive theoretical framework for understanding various spin relaxation processes in localized electrons and compares these with experimental observations.

Findings

Spin relaxation limited by hyperfine or spin-orbit interactions.

Energy relaxation governed by phonon-assisted hops.

Spin correlation influenced by exchange interaction or spin-flip scattering.

Abstract

The mechanisms that determine spin relaxation times of localized electrons in impurity bands of n-type semiconductors are considered theoretically and compared with available experimental data. The relaxation time of the non-equilibrium angular momentum is shown to be limited either by hyperfine interaction, or by spin-orbit interaction in course of exchange-induced spin diffusion. The energy relaxation time in the spin system is governed by phonon-assisted hops within pairs of donors with an optimal distance of about 4 Bohr radii. The spin correlation time of the donor-bound electron is determined either by exchange interaction with other localized electrons, or by spin-flip scattering of free conduction-band electrons. A possibility of optical cooling of the spin system of localized electrons is discussed.