Quantum phase transitions from competing short- and long-range interactions on a $\pi$-flux lattice

TL;DR

This study explores quantum phase transitions driven by competing short- and long-range interactions on a $\pi$-flux lattice, revealing a plaquette-dimer phase and potential deconfined quantum criticality through mean-field and quantum Monte Carlo methods.

Contribution

It provides the first detailed analysis of phase transitions involving cluster-charge interactions on a $\pi$-flux lattice, identifying a new plaquette-dimer phase and critical behavior.

Findings

Identification of a plaquette-dimer phase emerging at finite interaction strength.

Observation of an antiferromagnetic transition via spin structure factor.

Estimation of critical interaction and exponents indicating possible deconfined quantum critical point.

Abstract

Quantum phase transitions from the cluster-charge interaction, which is composed of competing short- and long-range interactions, are investigated on a $\pi$-flux lattice by using the mean-field theory and determinant quantum Monte Carlo (DQMC) simulations. Both methods identify a plaquette-dimer phase, which develops from a finite interaction strength. While its signature in DQMC is relatively weak, a obvious antiferromagnetic transition is revealed in the spin structure factor instead. The corresponding critical interaction and exponents are readily obtained by finite-size scalings, with the plaquette-dimer structure factor that can also be well scaled. These results suggest a possible deconfined quantum critical point between the plaquette-dimer and antiferromagnetic phases driven by the cluster-charge interaction on a $\pi$-flux lattice.