Ferromagnetic diagonal stripe states in the two-dimensional Hubbard model with $U\lesssim\infty$

TL;DR

This study uses variational Monte Carlo simulations to identify ferromagnetic diagonal stripe states as the ground state in a 2D Hubbard model at strong coupling, revealing energy gains from specific electron configurations.

Contribution

It demonstrates the stabilization of ferromagnetic diagonal stripe states in the strong coupling regime of the 2D Hubbard model, highlighting the energy mechanisms involved.

Findings

Ferromagnetic diagonal stripe states are stabilized at $U/t \\geq 16$.

Energy gain from holon movement and Coulomb interaction.

Stripe states are favored at hole density 1/8 with $t'/t=-0.30$.

Abstract

We have performed a variational Monte Carlo simulation to study the ground state of a two-dimensional Hubbard model on a square lattice in the strong coupling region. The energy gain of possible inhomogeneous electron states are computed as a function of $U$ when the hole density $\epsilon=1/8$ and next nearest-neighbor hopping $t'/t=-0.30$. The bond-centered ferromagnetic diagonal stripe state is stabilized in the strong coupling region ($U/t\geq$16), which is due to the gain of both kinetic energy and on-site Coulomb interaction energy due to the holon moving over the ferromagnetic domain and the gain of kinetic-exchange-interaction energy at the antiferromagnetic domain wall.