Discovery of superconductivity in Bi$_{2}$Te: evidence of universal behavior in an infinitely adaptive series under compression*

The end members of the infinitely adaptive (Bi$_{2})_{\mathrm{n}}$(Bi$_{2}$Te$_{3})_{\mathrm{m}}$ series, Bi and Bi$_{2}$Te$_{3}$, can be experimentally tuned to display topological surface states or superconductivity under appropriate conditions. An intermediate member of the series, Bi$_{2}$Te has been found to superconduct under similar conditions, transitioning from a semiconductor at ambient conditions to a metallic superconductor with a maximum $T_{c} =$ 9.1 K at 14.5 GPa. This represents a move towards universal behavior in the infinitely adaptive (Bi$_{2})_{\mathrm{n}}$(Bi$_{2}$Te$_{3})_{\mathrm{m}}$ series in which all of the superstructures converge into a metallic, superconducting state at high pressure. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under contract DE-AC52-07NA27344.