d-Mott phases in one and two dimensions

TL;DR

This paper investigates the emergence of d-Mott insulating phases and d-wave superconductivity in one- and two-dimensional Hubbard models using exact diagonalization, revealing a crossover from insulating to superconducting states near half-filling.

Contribution

It demonstrates the presence of d-Mott phases in both one- and two-dimensional Hubbard models and details the crossover to d-wave superconductivity near half-filling.

Findings

Reproduces the insulating d-Mott ground state in the two-leg Hubbard ladder.

Identifies a crossover to a strong coupling state truncating the Fermi surface.

Observes d-wave superconductivity on the remaining Fermi surface at lower scales.

Abstract

We use exact diagonalization to determine the spectrum of reduced Hamiltonians based on renormalization group flows to strong coupling. For the half-filled two-leg Hubbard ladder we reproduce the known insulating d-Mott groundstate with spin and charge gaps. For the saddle point regions of the two-dimensional Hubbard model near half-filling we find a crossover to a similar strong coupling state, which truncates the Fermi surface near the saddle points. At lower scales d-wave superconductivity appears on the remaining Fermi surface.