Chiral Phonon Mediated High-Temperature Superconductivity

TL;DR

This paper proposes a novel mechanism where chiral phonons mediate high-temperature superconductivity through a two-phonon process, leading to unconventional pairing and an inverse isotope effect, offering insights into high-$T_c$ superconductors.

Contribution

It introduces a new electron-chiral phonon interaction model involving two-phonon processes and predicts high-temperature superconductivity mediated by chiral phonons.

Findings

Chiral phonons can mediate an effective Hubbard U.

The mechanism induces unconventional high-$T_c$ superconductivity.

Numerical results show an inverse isotope effect.

Abstract

Breaking down the traditional perception on phonons which are achiral, the recent discovery of chiral phonon carrying angular momentum provides possible ways to couple electron, photon, spin, magnon and exciton, etc. We theoretically proposed an electron-chiral phonon interaction with two-phonon process, in contrast to conventional electron-phonon interaction, and a kind of effective Hubbard U through exchanging two chiral phonons is proposed. Taking two-dimensional diatomic honeycomb lattice as an example, we found this repulsive Hubbard U mediated by chiral phonons induces unconventional and high-temperature superconductivity. Moreover, the numerical calculations show an inverse isotope effect which is consistent with experimental observations in high-$T_c$ superconductors. Our finding on electron-chiral phonon and the associated Cooper pair provides a path to understand the high-$T_c$ superconductivity.