Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas
![Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas](https://ultracold.jqi.umd.edu/wp-content/uploads/2013/08/Fig_SpinInjection.png)
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 directly 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. We also create a spin-orbit coupled lattice and probe its spinful band structure, which features additional spin gaps and a fully gapped spectrum. In the presence of s-wave interactions, such systems should display induced p-wave pairing, topological superfluidity, and Majorana edge states.
1. Cheuk, L. et al. Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas. Phys. Rev. Lett. 109, 095302 (2012).