Band Structure and Superconductivity in Twisted Trilayer Graphene

TL;DR

This paper investigates the electronic band structure, symmetries, and superconducting phases of twisted trilayer graphene, revealing how interactions and perturbations influence its potential for superconductivity with various pairing symmetries.

Contribution

It provides a detailed analysis of the effects of long-range interactions and perturbations on the band structure and superconductivity in twisted trilayer graphene, extending understanding beyond bilayer systems.

Findings

Superconducting phases with different spin and valley symmetries identified.

Critical temperatures up to a few Kelvin predicted for realistic parameters.

Electronic structure modified similarly to twisted bilayer graphene by interactions.

Abstract

We study the symmetries of twisted trilayer graphene's band structure under various extrinsic perturbations, and analyze the role of long-range electron-electron interactions near the first magic angle. The electronic structure is modified by these interactions in a similar way to twisted bilayer graphene. We analyze electron pairing due to long-wavelength charge fluctuations, which are coupled among themselves via the Coulomb interaction and additionally mediated by longitudinal acoustic phonons. We find superconducting phases with either spin singlet/valley triplet or spin triplet/valley singlet symmetry, with critical temperatures of up to a few Kelvin for realistic choices of parameters.