Theory for Charge Density Wave and Orbital-Flux State in Antiferromagnetic Kagome Metal FeGe

Hai Yang Ma, Jia Xin Yin, M. Zahid Hasan, Jianpeng Liu

Research output: Contribution to journalArticlepeer-review

Abstract

We theoretically study the charge order and orbital magnetic properties of a new type of antiferromagnetic kagome metal FeGe. Based on first-principles density functional theory calculations, we study the electronic structures, Fermi-surface quantum fluctuations, as well as phonon properties of the antiferromagnetic kagome metal FeGe. It is found that charge density wave emerges in such a system due to a subtle cooperation between electron-electron interactions and electron-phonon couplings, which gives rise to an unusual scenario of interaction-triggered phonon instabilities, and eventually yields a charge density wave (CDW) state. We further show that, in the CDW phase, the ground-state current density distribution exhibits an intriguing star-of-David pattern, leading to flux density modulation. The orbital fluxes (or current loops) in this system emerge as a result of the subtle interplay between magnetism, lattice geometries, charge order, and spin-orbit coupling (SOC), which can be described by a simple, yet universal, tight-binding theory including a Kane-Mele-type SOC term and a magnetic exchange interaction. We further study the origin of the peculiar step-edge states in FeGe, which sheds light on the topological properties and correlation effects in this new type of kagome antiferromagnetic material.

Original languageEnglish (US)
Article number047103
JournalChinese Physics Letters
Volume41
Issue number4
DOIs
StatePublished - Apr 1 2024

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy

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