Valerio Peri, Caltech

"Superconductivity in materials with flat bands: Insights from the quantum geometry"

Abstract: Superconductivity in materials with flat bands underscores the crucial role that band geometry plays in determining correlated phases. Recent research has shown that the geometry of topologically non-trivial bands can greatly enhance the superfluid weight, leading to higher superconducting critical temperatures. Through auxiliary-field Monte Carlo simulations, we demonstrate the importance of quantum geometry beyond the mean-field regime. We further provide lower bounds for the critical temperature of multi-band systems based on their momentum space irreducible representations in all 2D space groups. Lastly, we shed light on the similarities and differences between superconductivity and boson superfluidity in flat bands.