  In this work, 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 (DFT) calculations, we have studied the
electronic structures, Fermi-surface quantum fluctuations, as well as phonon
properties of the antiferromagnetic kagome metal FeGe. We find that charge
density wave emerges in such a system due to a subtle cooperation between
electron-electron ($e$-$e$) 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
emerges 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 shed light on the topological
properties and correlation effects in this new type of kagome antiferromagnetic
material.
