We report the results of electrical resistivity, magnetic and thermodynamic measurements on polycrystalline SnSb, whose structure consists of stacks of Sb bilayers and Sn4Sb3 septuple layers along the c-axis. The material is found to be a weakly coupled, fully gapped, type-II superconductor with a bulk Tc of 1.50 K, while showing a zero resistivity transition at a significantly higher temperature of 2.48 K. The Sommerfeld coefficient and upper critical field, obtained from specific heat measurements, are 2.29 mJ/mol K and 520 Oe, respectively. Compositional inhomogeneity and strain effect at the grain boundaries are proposed as possible origins for the difference in resistive and bulk superconducting transitions.In addition, a comparison with the rock-salt structure SnAs superconductor is presented. Our results provide the first clear evidence of bulk superconductivity in a natural superlattice derived from a topological semimetal.
@article{arxiv.1808.08500,
title = {Supercondutivity in SnSb with natural superlattice structure},
author = {Bin Liu and Jifeng Wu and Yanwei Cui and Hangdong Wang and Yi Liu and Zhicheng Wang and Zhi Ren and Guanghan Cao},
journal= {arXiv preprint arXiv:1808.08500},
year = {2018}
}