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arXiv · 2411.10931

Competing phases in kagome magnet FeGe from functional renormalization

Pietro M. Bonetti·Yi Jiang·Haoyu Hu·Dumitru Călugăru·Michael M. Scherer·B. Andrei Bernevig·Laura Classen
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Abstract

The discovery of a charge density wave in FeGe extends the discussion of the nature of charge order in kagome metals to a magnetic compound. Motivated by this observation, we combine density functional theory (DFT) and functional-renormalization-group calculations to study interaction-induced Fermi-surface instabilities of the magnetic state of FeGe. We argue that the leading intra-band contribution to electronic correlations are approximately 2D and come from Van Hove points at the projected $M$~points. By varying parameters around DFT values, we determine a phase diagram for the quasi-2D scenario as function of on-site and nearest-neighbor interactions. We discuss universal aspects in the electronic mechanisms for the resulting phases, as well as the role of SU(2) symmetry breaking. We find FeGe to be in a regime of strong competition between $p$-wave charge density wave, $f$-wave pairing, and $d$-wave spin Pomeranchuk instabilities. This interplay can be influenced in favor of superconducting pairing for slightly increased nearest-neighbor interaction, suggesting a potential to induce superconductivity in FeGe.

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Pietro M. Bonetti, Yi Jiang, Haoyu Hu, Dumitru Călugăru, Michael M. Scherer, B. Andrei Bernevig, Laura Classen. 2024-11-17. Competing phases in kagome magnet FeGe from functional renormalization. https://arxiv.org/abs/2411.10931

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