Strong renormalization of the Fermi-surface topology close to the Mott transition

TL;DR

This paper investigates how the Fermi surface topology in the 2D Hubbard model is strongly renormalized near the Mott transition, revealing a crossover from metal to resonating valence-bond superconductor and violations of Luttinger's theorem.

Contribution

It introduces improved correlated wave functions to study Fermi surface topology changes near the Mott transition in the Hubbard model.

Findings

Significant Fermi surface topology renormalization near the Mott insulator

Identification of a crossover from metal to RVB superconductor

Detection of Luttinger theorem violation at low hole doping

Abstract

The underlying Fermi surface is a key concept for strongly-interacting electron models and has been introduced to generalize the usual notion of the Fermi surface to generic (superconducting or insulating) systems. By using improved correlated wave functions that contain backflow and Jastrow terms, we examine the two-dimensional $t{-}t^\prime$ Hubbard model and find a non-trivial renormalization of the topology of the underlying Fermi surface close to the Mott insulator. Moreover, we observe a sharp crossover region, which arises from the metal-insulator transition, from a weakly interacting metal at small coupling to a resonating valence-bond superconductor at intermediate coupling. A violation of the Luttinger theorem is detected at low hole dopings.