# Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene

## TL;DR

This paper investigates the superconducting properties of twisted bilayer graphene, focusing on superfluid weight and BKT transition temperature, highlighting differences between local and non-local interactions and emphasizing the role of multiband processes and quantum geometry.

## Contribution

It provides a detailed analysis of superfluid weight and BKT transition temperature in twisted bilayer graphene, incorporating both microscopic and low-energy models, and reveals qualitative differences based on interaction types.

## Key findings

- Superfluid weight and BKT temperature depend on interaction schemes.
- Quantum geometry influences superfluid properties in the flat band limit.
- Distinct experimental signatures predicted for local vs. non-local interactions.

## Abstract

We study superconductivity of twisted bilayer graphene with local and non-local attractive interactions. We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for microscopic tight-binding and low-energy continuum models. We predict qualitative differences between local and non-local interaction schemes which could be distinguished experimentally. In the flat band limit where the pair potential exceeds the band width we show that the superfluid weight and BKT temperature are determined by multiband processes and quantum geometry of the band.