Superconductivity and Fermi-surface nesting in the candidate Dirac semimetal NbC

We report the synthesis of single-crystal NbC, a transition metal carbide with various unusual properties. Transport, magnetic susceptibility, and specific heat measurements demonstrate that NbC is a conventional superconductor with a superconducting transition temperature (T-c) of 11.5 K. Our theoretical calculations show that NbC is a type-II Dirac semimetal with strong Fermi-surface nesting, which is supported by our angle-resolved photoemission spectroscopy (ARPES) measurement results. We also observed the superconducting gaps of NbC using ARPES and found some unconventional behaviors. These intriguing superconducting and topological properties, combined with the high corrosion resistance, make NbC an ideal platform for both fundamental research and device applications.