Magnetic fluctuations near the Van Hove singularity in the kagome-lattice Hubbard model at finite doping

Fuente: arXiv
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Main Authors: Wang, Jingyao, Jia, Zixuan, Fan, Zenghui, Duan, Qingzhuo, Ma, Tianxing
Format: Preprint
Published: 2026
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author Wang, Jingyao
Jia, Zixuan
Fan, Zenghui
Duan, Qingzhuo
Ma, Tianxing
author_facet Wang, Jingyao
Jia, Zixuan
Fan, Zenghui
Duan, Qingzhuo
Ma, Tianxing
contents The kagome-lattice Hubbard model attracts widespread interest due to its flat-band and Van Hove singularity features, which can give rise to unconventional magnetism. We employ determinant quantum Monte Carlo simulations to systematically investigate the uniform magnetic susceptibility across a range of on-site interactions and electron fillings on a two-dimensional kagome lattice. Beyond the Van Hove singularity, dominant ferromagnetic fluctuations emerge. Magnetic susceptibility grows markedly with increasing interaction strength and decreasing temperature, indicating that the Van Hove singularity acts as a critical point for the crossover of dominant magnetic fluctuations. Finite-size analysis further suggests the potential stabilization of a finite-temperature ferromagnetic phase. We also examine the sign problem to identify numerically reliable parameter regimes. These results provide valuable insights into controlling magnetic fluctuations in kagome systems and establish a computational framework for exploring flat-band physics in regimes characterized by novel quantum phases and competing orders.
format Preprint
id arxiv_https___arxiv_org_abs_2603_01004
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Magnetic fluctuations near the Van Hove singularity in the kagome-lattice Hubbard model at finite doping
Wang, Jingyao
Jia, Zixuan
Fan, Zenghui
Duan, Qingzhuo
Ma, Tianxing
Strongly Correlated Electrons
The kagome-lattice Hubbard model attracts widespread interest due to its flat-band and Van Hove singularity features, which can give rise to unconventional magnetism. We employ determinant quantum Monte Carlo simulations to systematically investigate the uniform magnetic susceptibility across a range of on-site interactions and electron fillings on a two-dimensional kagome lattice. Beyond the Van Hove singularity, dominant ferromagnetic fluctuations emerge. Magnetic susceptibility grows markedly with increasing interaction strength and decreasing temperature, indicating that the Van Hove singularity acts as a critical point for the crossover of dominant magnetic fluctuations. Finite-size analysis further suggests the potential stabilization of a finite-temperature ferromagnetic phase. We also examine the sign problem to identify numerically reliable parameter regimes. These results provide valuable insights into controlling magnetic fluctuations in kagome systems and establish a computational framework for exploring flat-band physics in regimes characterized by novel quantum phases and competing orders.
title Magnetic fluctuations near the Van Hove singularity in the kagome-lattice Hubbard model at finite doping
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2603.01004