Competing orders in the 2D half-filled SU(2N) Hubbard model through the pinning field quantum Monte-Carlo simulations

TL;DR

This study uses quantum Monte Carlo simulations to explore magnetic orders in the 2D SU(2N) Hubbard model, revealing non-monotonic Neel order behavior and a phase transition to a dimer phase at strong coupling.

Contribution

It provides the first non-perturbative analysis of magnetic properties in the 2D SU(2N) Hubbard model with pinning fields, highlighting novel order behaviors.

Findings

Neel order exists for SU(4) and SU(6) at small/intermediate U

Neel moments show non-monotonic U dependence, unlike SU(2)

Transition to columnar dimer phase in SU(6) at strong U

Abstract

We non-perturbatively investigate the ground state magnetic properties of the 2D half-filled SU($2N$) Hubbard model in the square lattice by using the projector determinant quantum Monte Carlo simulations combined with the method of local pinning fields. Long-range Neel orders are found for both the SU(4) and SU(6) cases at small and intermediate values of $U$. In both cases, the long-range Neel moments exhibit non-monotonic behavior with respect to $U$, which first grow and then drop as $U$ increases. This result is fundamentally different from the SU(2) case in which the Neel moments increase monotonically and saturate. In the SU(6) case, a transition to the columnar dimer phase is found in the strong interaction regime.