Real-Space Topology and Charge Order in the Haldane-Holstein Model
Sebastião Dos A Sousa-Júnior1, Julián Faúndez2, Tarik P Cysne3
1University of Houston, Department of Physics, Houston, Texas 77204, USA.
Physical Review Letters
|July 10, 2026
Summary
Electron-phonon coupling can destroy topological properties in Chern insulators, causing an abrupt transition to a charge-density wave state. This collapse is marked by clear experimental signatures, offering insights into correlated topological platforms.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Topological Phases of Matter
Background:
- Chern insulators are topological states of matter with unique electronic properties.
- Electron-phonon interactions are crucial for understanding material behavior but can complicate topological phases.
- The Haldane-Holstein model provides a framework to study interplay between topology and electron-phonon coupling.
Purpose of the Study:
- To investigate how dynamical electron-phonon interactions destabilize topological order in a half-filled Haldane-Holstein model.
- To provide an unbiased characterization of the transition from a Chern insulator to a charge-density wave phase.
- To identify experimental signatures for detecting the collapse of Chern topology.
Main Methods:
- Determinant quantum Monte Carlo simulations were employed for unbiased numerical analysis.
- Analysis included many-body Bott index and real-space local Chern marker calculations.
- Spectral and open-boundary calculations were used to probe gap closing and boundary effects.
Main Results:
- Increasing electron-phonon coupling drives a first-order phase transition from Chern insulator to a charge-density wave.
- The transition is marked by the collapse of topological indices and the emergence of charge order.
- Gap closing and loss of boundary spectral weight signal the topological transition.
Conclusions:
- Electron-phonon coupling can induce a discontinuous collapse of Chern topology.
- The study provides experimentally relevant signatures for correlated topological platforms.
- Dynamical phonons can act as a sublattice mass, destabilizing topological order.
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