Superconductivity from collective excitations in magic angle twisted bilayer graphene

TL;DR

This paper proposes a purely electronic mechanism for superconductivity in twisted bilayer graphene near the magic angle, using a theoretical framework that aligns with experimental observations.

Contribution

It introduces a new electronic mechanism for superconductivity in tBG based on collective excitations, supported by a one-parameter lattice model and Migdal-Eliashberg theory.

Findings

Superconductivity can arise from collective electronic modes in tBG.

The model predicts an asymmetric superconducting dome.

Critical temperatures predicted match experimental data.

Abstract

A purely electronic mechanism is proposed for the unconventional superconductivity recently observed in twisted bilayer graphene (tBG) close to the magic angle. Using the Migdal-Eliashberg framework on a one parameter effective lattice model for tBG we show that a superconducting state can be achieved by means of collective electronic modes in tBG. We posit robust features of the theory, including an asymmetrical superconducting dome and the magnitude of the critical temperature that are in agreement with experiments.