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

By Lanpo He, Yating Jia, Si-jia Zhang, X. Hong, C. Jin, Shiyan Li. npj Quantum Materials, 2016

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The 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. Cd3As2 is shown to become a topological superconductor candidate under pressure. Topological superconductors are typically obtained by modifying the surface electronic structure of topological insulators. Doping and pressure have been demonstrated as two ways to achieve this. However, pressure has yet to be explored as a route to topological superconductivity in the recently discovered three-dimensional (3D) Dirac semimetals, the Fermi surface of which exhibits 3D Dirac points. The electrical resistance of Cd3As2 single crystals have now been investigated under pressure: superconductivity initiates at around 8.5 GPa, and increases to 4 K at approximately 21 GPa. A structural phase transition is additionally evidenced from x-ray diffraction data at roughly 3.5 GPa. This study demonstrates that pressure could be a feasible route to achieve topological superconductivity in 3D topological Dirac semimetals.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/6a01f84fd75528a3b18b1d8ad5abb6bf15115cb7