Systematic Analysis of Frustration Effects in Anisotropic Checkerboard Lattice Hubbard Model

TL;DR

This paper investigates the ground state phases of the anisotropic checkerboard lattice Hubbard model, revealing the emergence of a plaquette-singlet insulator and mapping the phase diagram using advanced computational methods.

Contribution

It provides a systematic analysis of frustration effects in the Hubbard model on an anisotropic checkerboard lattice, identifying key phases and ruling out spin-liquid states.

Findings

Identification of plaquette-singlet insulator phase

Phase diagram mapping in U and t'/t parameters

Absence of spin-liquid insulating states

Abstract

We study the ground state properties of the geometrically frustrated Hubbard model on the anisotropic checkerboard lattice with nearest-neighbor hopping $t$ and next nearest-neighbor hopping $t'$. By using the path-integral renormalization group method, we study the phase diagram in the parameter space of the Hubbard interaction $U$ and the frustration-control parameter $t'/t$. Close examinations of the effective hopping, the double occupancy, the momentum distribution and the spin/charge correlation functions allow us to determine the phase diagram at zero temperature, where the plaquette-singlet insulator emerges besides the antiferromagnetic insulator and the paramagnetic metal. Spin-liquid insulating states without any kind of symmetry breaking cannot be found in our frustrated model.