Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas

TL;DR

This paper demonstrates the creation and detection of spin-orbit coupling in a controllable atomic Fermi gas using spin-injection spectroscopy, revealing the band structure and potential for topological superfluidity.

Contribution

It introduces a method to realize and characterize spin-orbit coupling in an atomic Fermi gas, advancing the study of topological phases in quantum matter.

Findings

Spin-orbit gap characterized via spin-injection spectroscopy.

System acts as a spin diode within the gap.

Creation of a spin-orbit coupled lattice with a tunable band structure.

Abstract

The coupling of the spin of electrons to their motional state lies at the heart of recently discovered topological phases of matter. Here we create and detect spin-orbit coupling in an atomic Fermi gas, a highly controllable form of quantum degenerate matter. We reveal the spin-orbit gap via spin-injection spectroscopy, which characterizes the energy-momentum dispersion and spin composition of the quantum states. For energies within the spin-orbit gap, the system acts as a spin diode. To fully inhibit transport, we open an additional spin gap, thereby creating a spin-orbit coupled lattice whose spinful band structure we probe. In the presence of s-wave interactions, such systems should display induced p-wave pairing, topological superfluidity, and Majorana edge states.