Magnetic correlations and superconducting pairing near higher-order Van Hove singularities

Fuente: arXiv
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Main Authors: Wei, Zheng, Cai, Yanmei, Wen, Boyang, Ma, Tianxing
Format: Preprint
Published: 2025
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_version_ 1866912867652993024
author Wei, Zheng
Cai, Yanmei
Wen, Boyang
Ma, Tianxing
author_facet Wei, Zheng
Cai, Yanmei
Wen, Boyang
Ma, Tianxing
contents Higher-order Van Hove singularities in strongly correlated electron systems provide a fertile ground for emergent electronic orders and superconductivity. This study investigates the interplay between magnetic fluctuations and superconducting pairing near higher-order Van Hove singularities on the honeycomb lattice, a paradigmatic platform relevant to graphene. By incorporating third-nearest-neighbor hopping \(t''\), we uncover a universal crossover: ferromagnetic fluctuations dominate below the higher-order Van Hove filling, while antiferromagnetic fluctuations take over toward half filling. A key finding is that the already dominant \(f_n\)-wave pairing is enhanced in the critical region of this magnetic crossover by the higher-order Van Hove. This enhancement is driven by the synergistic effect of the higher-order Van Hove singularities-induced divergent density of states and the competing magnetic fluctuations. Although increased hopping parameters generally suppress superconducting correlation, we identify a critical \(t''\) that anomalously enhances pairing via the higher-order Van Hove renormalization. Furthermore, the nearest-neighbor Coulomb interaction suppresses the pairing correlation function in a sign-independent manner. Our results clarify the competitive mechanisms between magnetic fluctuations and unconventional superconductivity in higher-order Van Hove singularities systems, offering a theoretical basis for tailoring quantum phases in graphene-based materials via band engineering.
format Preprint
id arxiv_https___arxiv_org_abs_2505_10358
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Magnetic correlations and superconducting pairing near higher-order Van Hove singularities
Wei, Zheng
Cai, Yanmei
Wen, Boyang
Ma, Tianxing
Strongly Correlated Electrons
Superconductivity
Higher-order Van Hove singularities in strongly correlated electron systems provide a fertile ground for emergent electronic orders and superconductivity. This study investigates the interplay between magnetic fluctuations and superconducting pairing near higher-order Van Hove singularities on the honeycomb lattice, a paradigmatic platform relevant to graphene. By incorporating third-nearest-neighbor hopping \(t''\), we uncover a universal crossover: ferromagnetic fluctuations dominate below the higher-order Van Hove filling, while antiferromagnetic fluctuations take over toward half filling. A key finding is that the already dominant \(f_n\)-wave pairing is enhanced in the critical region of this magnetic crossover by the higher-order Van Hove. This enhancement is driven by the synergistic effect of the higher-order Van Hove singularities-induced divergent density of states and the competing magnetic fluctuations. Although increased hopping parameters generally suppress superconducting correlation, we identify a critical \(t''\) that anomalously enhances pairing via the higher-order Van Hove renormalization. Furthermore, the nearest-neighbor Coulomb interaction suppresses the pairing correlation function in a sign-independent manner. Our results clarify the competitive mechanisms between magnetic fluctuations and unconventional superconductivity in higher-order Van Hove singularities systems, offering a theoretical basis for tailoring quantum phases in graphene-based materials via band engineering.
title Magnetic correlations and superconducting pairing near higher-order Van Hove singularities
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2505.10358