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

TL;DR

Applying high pressure to the quasi-one-dimensional topological insulator Bi4I4 induces superconductivity and triggers multiple topological quantum phase transitions, revealing new insights into pressure-tuned topological and superconducting states.

Contribution

This study demonstrates pressure-induced superconductivity and topological phase transitions in Bi4I4, a quasi-one-dimensional topological insulator, expanding understanding of pressure effects in low-dimensional topological materials.

Findings

Superconductivity appears in Bi4I4 above a certain pressure threshold.

The superconducting transition temperature reaches 6 K at 23 GPa.

Multiple topological quantum phase transitions are predicted under pressure.

Abstract

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- 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 \b{eta}-Bi4I4 by applying high pressure. Superconductivity is observed in \b{eta}-Bi4I4 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 Tc 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.