Bulk superconductivity in the Dirac semimetal T1Sb

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 T1Sb compound with a CsC1-type structure. The band structure calculations show that T1Sb is a Dirac semimetal when spin-orbit coupling is considered. T1Sb is first determined to be a type-II superconductor with [T.sub.c]=4.38 K, [H.sub.c1](0)=148 Oe, [H.sub.c2](0)=1.12 T, and [K.sub.GL]=10.6. We also confirm that T1Sb is a moderately coupled s- wave superconductor. Although we cannot determine the band near the Fermi level [E.sub.F] that is responsible for superconductivity, its coexistence with topological surface states implies that the T1Sb compound may be a simple material platform to realize the fault-tolerant quantum computations. s-wave superconductor, Dirac semimetal, topological superconductor PACS number(s): 31.15.Ew, 74.25.Op, 74.25.Fy, 74.25.Jb