Turning a band insulator into an exotic superconductor

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 favoured via a conventional phonon-mediated mechanism, as driven by an unusual, almost singular behaviour of the electron-phonon interaction at long wavelengths. This may provide a new platform for our understanding of superconductivity phenomena in doped band insulators. © 2014 Macmillan Publishers Limited. All rights reserved.