Ultrafast symmetry modulation and induced magnetic excitation in the Kagome metal RbV3Sb5

TL;DR

This study demonstrates how ultrafast laser excitation can induce symmetry breaking and magnetic phases in the Kagome metal RbV3Sb5 by selectively exciting phonon modes, revealing a spin-driven pathway for nonequilibrium state control.

Contribution

The paper uncovers a microscopic mechanism for laser-induced symmetry breaking in RbV3Sb5 via first-principles simulations, highlighting a spin-driven pathway distinct from previous theories.

Findings

Selective phonon excitation breaks symmetries and stabilizes a ferrimagnetic phase.

Induces a sizable anomalous Hall effect in the nonequilibrium state.

Reveals a spin-driven mechanism for symmetry breaking under optical fields.

Abstract

Light-matter interaction in frustrated Kagome metals enables access to hidden quantum states, yet the microscopic origin of symmetry breaking under ultrafast excitation remains elusive. Here, we uncover a microscopic mechanism for laser-induced symmetry breaking in RbV3Sb5 through first-principles real-time simulations. Selective excitation of a single-QM phonon mode dynamically breaks both rotational and time-reversal symmetries within the 2X2X1 charge density wave (CDW) superlattice. The resulting anisotropic lattice distortion lifts geometric frustration and stabilizes a nonequilibrium ferrimagnetic phase, accompanied by a sizable intrinsic anomalous Hall effect. Distinct from prior interpretations based on orbital antiferromagnetism or extrinsic perturbations, our findings reveal a spin-driven pathway for symmetry breaking under strong optical fields. These results provide a microscopic foundation for exploring how spin, lattice and charge degrees of freedom are intertwined in nonequilibrium correlated states.