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

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…

• NS
  National Science Foundation
• DA
  David and Lucile Packard Foundation
• DA
  Defense Advanced Research Projects Agency
• MU
  Multidisciplinary University Research Initiative
• EA
  Engineering and Physical Sciences Research Council

  Awards: EP/I010580/1, EP/I010580/1
• OO
  Office of Naval Research
• AF
  Air Force Office of Scientific Research
• AR
  Army Research Office