Bulk superconductivity in the Dirac semimetal TlSb

A feasible strategy for realizing the Majorana fermions is searching for a simple compound with both bulk superconductivity and Dirac surface states. In this paper, we perform calculations of electronic band structure, the Fermi surface, and the surface states, and measure the resistivity, magnetization, and specific heat of a TlSb compound with a CsCl-type structure. The band structure calculations show that TlSb is a Dirac semimetal when spin-orbit coupling is considered. TlSb is first determined to be a type-II superconductor with Tc=4.38 K, Hc1(0) = 148 Oe, Hc2(0)=1.12 T, and κGL = 10.6. We also confirm that TlSb is a moderately coupled s-wave superconductor. Although we cannot determine the band near the Fermi level EF that is responsible for superconductivity, its coexistence with topological surface states implies that the TlSb compound may be a simple material platform to realize the fault-tolerant quantum computations.