Pressure-induced superconductivity in the three-dimensional topological Dirac semimetal Cd3As2

Lanpo He,Sijia Zhang,Xiaochen Hong,Yating Jia,Changqing Jin,Shiyan Li

doi:10.1038/npjquantmats.2016.14

Abstract

AbstractThe recently discovered Dirac and Weyl semimetals are new members of topological materials. Starting from them, topological superconductivity may be achieved, e.g., by carrier doping or applying pressure. Here we report high-pressure resistance and X-ray diffraction study of the three-dimensional topological Dirac semimetal Cd3As2. Superconductivity with Tc≈2.0 K is observed at 8.5 GPa. The Tc keeps increasing to about 4.0 K at 21.3 GPa, then shows a nearly constant pressure dependence up to the highest pressure 50.9 GPa. The X-ray diffraction measurements reveal a structure phase transition around 3.5 GPa. Our observation of superconductivity in pressurised topological Dirac semimetal Cd3As2 provides a new candidate for topological superconductor, as argued in a recent point contact study and a theoretical work.

Highlights

In recent few years, the search for topological superconductors (TSCs) has been a hot topic in condensed matter physics.[1,2] TheTSCs have a full pairing gap in the bulk and gapless surface states consisting of Majorana fermions.[1]
DISCUSSION we discuss whether the superconducting state of Cd3As2 under high pressure is topological or not
Considering its special topological property, they suggested that Cd3As2 under high pressure is a candidate of the TSC.[44]

Summary

Introduction

The search for topological superconductors (TSCs) has been a hot topic in condensed matter physics.[1,2] TheTSCs have a full pairing gap in the bulk and gapless surface states consisting of Majorana fermions.[1]. By doping, CuxBi2Se3 and Cux(PbSe)5(Bi2Se3)[6] are considered to be candidates for TSCs,[3,4,5,6] while Sn1 − xInxTe is considered as a candidate for topological crystalline superconductor.[7,8] Under pressure, Bi2Te3, Bi2Se3, Sb2Te3 and Sb2Se3 become superconducting, which are regarded as candidates for TSCs.[9,10,11,12,13,14] Note that there are debates on whether these candidates are TSCs,[9,10,11,12,13,14,15,16,17] further experimental works are needed to definitely identify a TSC and manipulate the Majorana fermions on its surface

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Conclusion