Two-Beam Spin Noise Spectroscopy

TL;DR

This paper introduces a two-beam spin noise spectroscopy method to analyze spin transport and interactions in semiconductors, enabling measurement of spin-orbit coupling, relaxation times, and distinguishing different electron spin noise sources.

Contribution

It develops a theoretical framework for two-beam spin noise spectroscopy in semiconductor wires with spin-orbit interaction, including multiple relaxation channels and finite laser beam sizes.

Findings

Predicts peak shifts in spin noise spectra depending on spin-orbit strength and beam separation.

Provides a method to separate conduction electron spin noise from localized electron noise.

Suggests applications in studying various materials and systems.

Abstract

We propose a method of two-beam spin noise spectroscopy to test the spin transport at equilibrium via analysis of correlations between time-shifted spin fluctuations at different space locations. This method allows one to determine the strength of spin-orbit interaction and spin relaxation time and separate spin noise of conducting electrons from the background noise of localized electrons. We formulate a theory of two-beam spin noise spectroscopy in semiconductor wires with Bychkov-Rashba spin-orbit interaction taking into account several possible spin relaxation channels and finite size of laser beams. Our theory predicts a peak shift with respect to the Larmor frequency to higher or lower frequencies depending on the strength of spin orbit interaction and distance between the beams. The two-beam spin noise spectroscopy could find applications in experimental studies of semiconductors, emergent materials and many other systems.