Pressure-induced superconductivity and topological quantum phase transitions in a quasi-one-dimensional topological insulator: Bi4I4

• Published in: npj quantum materials 2018-01, Vol.3 (1), Article 4
• Main Authors: Qi, Yanpeng, Shi, Wujun, Werner, Peter, Naumov, Pavel G., Schnelle, Walter, Wang, Lei, Rana, Kumari Gaurav, Parkin, Stuart, Medvedev, Sergiy A., Yan, Binghai, Felser, Claudia
• Format: Article
• Language: English
• Subjects: 639/301/119/2792; 639/766/119/1003; Anomalies; Bismuth; Condensed Matter Physics; Electrical resistivity; Mathematical analysis; Phase transitions; Physics; Physics and Astronomy; Pressure dependence; Quantum computing; Quantum Physics; Structural Materials; Structural stability; Superconductivity; Surfaces and Interfaces; Temperature dependence; Thin Films; Topological insulators; Topology; Transition temperature
• ISSN: 2397-4648; 2397-4648
• DOI: 10.1038/s41535-018-0078-3

Superconductivity and topological quantum states are two frontier fields of research in modern condensed matter physics. The realization of superconductivity in topological materials is highly desired; however, superconductivity in such materials is typically limited to two-dimensional or three-dimensional materials and is far from being thoroughly investigated. In this work, we boost the electronic properties of the quasi-one-dimensional topological insulator bismuth iodide β-Bi 4 I 4 by applying high pressure. Superconductivity is observed in β-Bi 4 I 4 for pressures, where the temperature dependence of the resistivity changes from a semiconducting-like behavior to that of a normal metal. The superconducting transition temperature T c increases with applied pressure and reaches a maximum value of 6 K at 23 GPa, followed by a slow decrease. Our theoretical calculations suggest the presence of multiple pressure-induced topological quantum phase transitions as well as a structural–electronic instability. Topological insulators: pressure induces superconductivity Pressure-induced superconductivity is observed in topological insulator β-Bi 4 I 4 , and multiple topological phase transitions are predicted from ab initio calculations. An international team led by Binghai Yan and Claudia Felser from Max Planck Institute for Chemical Physics of Solids in Germany investigated the high-pressure behavior of the quasi-one-dimensional topological insulator β-Bi 4 I 4 . The resistivity under pressure shows a semiconductor-to-metal transition, followed by zero resistivity above 17.6 GPa, indicating the emergence of superconductivity. The critical transition temperature reaches a maximum of 6 K at 23 GPa. Ab initio calculations suggest multiple topological phase transitions, which show corresponding anomalies in the pressure-dependent resistivity data. These results are helpful in making β-Bi 4 I 4 a promising candidate of possible topological superconductivity, which is a first step to quantum computation.