Altermagnetism and beyond in the $t$-$t^\prime$-$δ$ Fermi-Hubbard model

Fuente: arXiv
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Main Authors: He, Saisai, Zhao, Jize, Luo, Hong-Gang, Hu, Shijie
Format: Preprint
Published: 2025
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author He, Saisai
Zhao, Jize
Luo, Hong-Gang
Hu, Shijie
author_facet He, Saisai
Zhao, Jize
Luo, Hong-Gang
Hu, Shijie
contents In this work, we revisit the phase diagram of the $t$-$t^\prime$-$δ$ Fermi-Hubbard model on the square lattice to gain a more comprehensive understanding of this correlated model at half filling. This model has recently become a prominent topic of research because it hosts altermagnetic phases. Using mean-field analysis, we identify four metallic phases and two insulating phases with nontrivial magnetic orders at an intermediate value of $δ= 0.5$, presenting a rich ground-state phase diagram in the $U$-$t^\prime$ plane. We also highlight the distinct features of the Fermi surface topology for each metallic phase. To go beyond the mean-field theory, we employ the density-matrix renormalization group method to simulate the ground state numerically. The phase boundaries are determined from the discontinuities and peaks in the entanglement entropy and magnetizations. In addition to the phases identified in the mean-field theory, we find a valence-bond solid state in a narrow intermediate-$t'$ region. Our work offers a firm step forward in understanding the complex behaviors of correlated electrons in the $t$-$t^\prime$-$δ$ Hubbard model over a large parameter space.
format Preprint
id arxiv_https___arxiv_org_abs_2503_08362
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Altermagnetism and beyond in the $t$-$t^\prime$-$δ$ Fermi-Hubbard model
He, Saisai
Zhao, Jize
Luo, Hong-Gang
Hu, Shijie
Strongly Correlated Electrons
In this work, we revisit the phase diagram of the $t$-$t^\prime$-$δ$ Fermi-Hubbard model on the square lattice to gain a more comprehensive understanding of this correlated model at half filling. This model has recently become a prominent topic of research because it hosts altermagnetic phases. Using mean-field analysis, we identify four metallic phases and two insulating phases with nontrivial magnetic orders at an intermediate value of $δ= 0.5$, presenting a rich ground-state phase diagram in the $U$-$t^\prime$ plane. We also highlight the distinct features of the Fermi surface topology for each metallic phase. To go beyond the mean-field theory, we employ the density-matrix renormalization group method to simulate the ground state numerically. The phase boundaries are determined from the discontinuities and peaks in the entanglement entropy and magnetizations. In addition to the phases identified in the mean-field theory, we find a valence-bond solid state in a narrow intermediate-$t'$ region. Our work offers a firm step forward in understanding the complex behaviors of correlated electrons in the $t$-$t^\prime$-$δ$ Hubbard model over a large parameter space.
title Altermagnetism and beyond in the $t$-$t^\prime$-$δ$ Fermi-Hubbard model
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2503.08362