Effect of exchange interaction on the spin fluctuations of localized electrons

TL;DR

This paper develops a microscopic theory for spin fluctuations in localized electrons, incorporating hyperfine and exchange interactions, revealing how exchange interaction influences spin noise spectra in semiconductors.

Contribution

It introduces a cluster model to analyze spin noise spectra, accounting for exchange interactions, which was not previously modeled in detail.

Findings

Exchange interaction causes a shift of the spin-fluctuation spectrum peak to lower frequencies.

Electron-electron exchange interaction averages out nuclear field randomness.

The model explains experimental observations of spin noise in localized electron systems.

Abstract

In this paper a microscopic theory of spin fluctuations in an ensemble of electrons localized on donors in a bulk semiconductor has been developed. Both the hyperfine interaction of the electron spin with spins of lattice nuclei and the exchange interaction between the electrons have been taken into account. We propose a model of clusters to calculate spin noise spectra of the ensemble of localized charge carriers. It has been shown that the electron-electron exchange interaction leads to an effective averaging of random nuclear fields and a shift of the peak in the spin-fluctuation spectrum towards lower frequencies.