Pressure-Dependent Superconductivity in Topological Dirac Semimetal SrCuBi.

The discovery of superconducting states in diverse topological materials generated a burgeoning interest to explore a topological superconductor and to realize a fault-tolerant topological quantum computation. A variety of routes to realize topological superconductors have been proposed and many types of topological materials have been developed. However, a pristine topological material with a natural superconducting state is relatively rare as compared to topological materials with artificially induced superconductivity. Here, we report that the planar honeycomb structured three-dimensional (3D) topological Dirac semimetal (TDS) SrCuBi, which is the Zintl phase, shows a natural surface superconductivity at 2.1 K under ambient pressure. It is clearly identified from theoretical calculations that a topologically non-trivial state exists on the (100) surface. Further, its superconducting transition temperature (T c ) increases by applying pressure, exhibiting a maximal T c of 4.8 K under 6.2 GPa. We believe that this discovery opens up a new possibility of exploring exotic Majorana fermions at the surface of 3D TDS superconductors. This article is protected by copyright. All rights reserved.