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Autores principales: Fang, Yi-Kun, Wang, Jing
Formato: Preprint
Publicado: 2025
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Acceso en línea:https://arxiv.org/abs/2509.05558
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author Fang, Yi-Kun
Wang, Jing
author_facet Fang, Yi-Kun
Wang, Jing
contents We present a systematic investigation of all sixteen marginally relevant fermion-fermion interactions in two-dimensional time-reversal symmetry-breaking kagomé semimetals hosting a quadratic band crossing point. Employing a momentum-shell renormalization group approach that treats every interaction on equal footing, we derive energy-dependent flow equations that capture the hierarchical evolutions of interaction parameters. Our analysis begins by tracking the energy-dependent flows of fermion-fermion interactions. The interaction couplings go towards divergence at a critical energy scale, signaling quantum critical behavior. Such behavior is characterized by a certain fixed point (FP) whose characteristics depends intimately on structural parameters $d_{0,1,2,3}$ that cluster the microscopic model into rotationally symmetric and asymmetric cases. Then, we identify two stable FPs in the rotationally symmetric and nine additional FPs in asymmetric case dubbed FP$_{1-10}$. Their boundary conditions are approximately demarcated and established by linear and plane fitting techniques in the structural parameter space. Furthermore, we examine distinct interaction-driven instabilities nearby these FPs by incorporating the relevant external source terms and computing their susceptibilities. It indicates that the charge density wave and superconductivity become dominant at FP$_{2,4,5,6,8}$ and FP$_{1,9,10}$, while the $x$-current and bond density prevail at FP$_3$ and FP$_7$, respectively. In addition to these leading states, several underlying subordinate instabilities are presented as well. These results would be helpful to further study the low-energy critical behavior in 2D kagomé QBCP and related materials.
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publishDate 2025
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spellingShingle Interaction-driven quantum criticality in two-dimensional quadratic band crossing semimetals with time-reversal symmetry breaking
Fang, Yi-Kun
Wang, Jing
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
We present a systematic investigation of all sixteen marginally relevant fermion-fermion interactions in two-dimensional time-reversal symmetry-breaking kagomé semimetals hosting a quadratic band crossing point. Employing a momentum-shell renormalization group approach that treats every interaction on equal footing, we derive energy-dependent flow equations that capture the hierarchical evolutions of interaction parameters. Our analysis begins by tracking the energy-dependent flows of fermion-fermion interactions. The interaction couplings go towards divergence at a critical energy scale, signaling quantum critical behavior. Such behavior is characterized by a certain fixed point (FP) whose characteristics depends intimately on structural parameters $d_{0,1,2,3}$ that cluster the microscopic model into rotationally symmetric and asymmetric cases. Then, we identify two stable FPs in the rotationally symmetric and nine additional FPs in asymmetric case dubbed FP$_{1-10}$. Their boundary conditions are approximately demarcated and established by linear and plane fitting techniques in the structural parameter space. Furthermore, we examine distinct interaction-driven instabilities nearby these FPs by incorporating the relevant external source terms and computing their susceptibilities. It indicates that the charge density wave and superconductivity become dominant at FP$_{2,4,5,6,8}$ and FP$_{1,9,10}$, while the $x$-current and bond density prevail at FP$_3$ and FP$_7$, respectively. In addition to these leading states, several underlying subordinate instabilities are presented as well. These results would be helpful to further study the low-energy critical behavior in 2D kagomé QBCP and related materials.
title Interaction-driven quantum criticality in two-dimensional quadratic band crossing semimetals with time-reversal symmetry breaking
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2509.05558