Superconductivity induced by strong electron-exciton coupling in doped atomically thin semiconductor heterostructures

TL;DR

This paper proposes a mechanism for superconductivity in atomically thin semiconductors mediated by electron-exciton interactions, revealing a BCS-BEC crossover and potential for high critical temperatures.

Contribution

It introduces a model incorporating strong electron-exciton coupling and strong-coupling physics, extending beyond phonon-mediated superconductivity, and predicts high-temperature superconductivity in 2D heterostructures.

Findings

Emergence of BCS-BEC crossover due to strong electron-exciton interactions

Superconductivity with critical temperatures up to 10% of Fermi temperature

Light bipolarons enabling high critical temperatures in 2D heterostructures

Abstract

We study a mechanism to induce superconductivity in atomically thin semiconductors where excitons mediate an effective attraction between electrons. Our model includes interaction effects beyond the paradigm of phonon-mediated superconductivity and connects to the well-established limits of Bose and Fermi polarons. By accounting for the strong-coupling physics of trions, we find that the effective electron-exciton interaction develops a strong frequency and momentum dependence accompanied by the system undergoing an emerging BCS-BEC crossover from weakly bound $s$-wave Cooper pairs to a superfluid of bipolarons. Even at strong-coupling the bipolarons remain relatively light, resulting in critical temperatures of up to 10\% of the Fermi temperature. This renders heterostructures of two-dimensional materials a promising candidate to realize superconductivity at high critical temperatures set by electron doping and trion binding energies.