Turning a Band Insulator Into an Exotic Superconductor

TL;DR

This paper demonstrates that doped Bi$_{2}$Se$_{3}$ can host unconventional p-wave-like superconductivity mediated by phonons, driven by unique electron-phonon interactions, challenging the traditional association with electronic correlations.

Contribution

It reveals that an exotic superconducting state can arise from a conventional phonon mechanism in doped band insulators, specifically in Bi$_{2}$Se$_{3}$, due to unusual electron-phonon interactions.

Findings

Unconventional p-wave-like state can be favored in doped Bi$_{2}$Se$_{3}$

Electron-phonon interaction exhibits almost singular behavior at long wavelengths

Superconductivity may originate from conventional phonon mechanisms in doped insulators

Abstract

Understanding exotic, non s--wave--like states of Cooper pairs is important and may lead to new superconductors with higher critical temperatures and novel properties. Their existence is known to be possible but has always been thought to be associated with non--traditional mechanisms of superconductivity where electronic correlations play an important role. Here we use a first principles linear response calculation to show that in doped Bi$_{2}$Se$_{3}$ an unconventional p--wave--like state can be favored via a conventional phonon--mediated mechanism, as driven by an unusual, almost singular behavior of the electron--phonon interaction at long wavelengths. This may provide a new platform for our understanding superconductivity phenomena in doped band insulators.