Effect of Induced Spin-Orbit Coupling for Atoms via Laser Fields

TL;DR

This paper proposes an experimental scheme to induce and study spin-orbit coupling in a 2D Fermi atomic gas using laser fields, revealing tunable effective mass effects and observable cloud splitting behaviors.

Contribution

It introduces a novel method to induce and control spin-orbit coupling in atomic gases, enabling exploration of effective mass phenomena and cloud dynamics.

Findings

Induced spin-orbit coupling can be of Dresselhaus and Rashba types.

The effective mass of atoms can be tuned between positive and negative values.

Cloud expansion dynamics show splitting into multiple clouds based on effective mass.

Abstract

We propose an experimental scheme to study spin-orbit coupling effects in a of two-dimensional (2D) Fermi atomic gas cloud by coupling its internal electronic states (pseudospins) to radiation in a delta configuration. The induced spin-orbit coupling can be of the Dresselhaus and Rashba type with and without a Zeeman term. We show that the optically induced spin-orbit coupling can lead to a spin-dependent effective mass under appropriate condition, with one of them able to be tuned between positive and negative effective mass. As a direct observable we show that in the expansion dynamics of the atomic cloud the initial atomic cloud splits into two clouds for the positive effective mass case regime, and into four clouds for the negative effective mass regime.