English

Kibble-Zurek behavior in a topological phase transition with a quadratic band crossing

Statistical Mechanics 2024-10-21 v2 Disordered Systems and Neural Networks Quantum Gases Strongly Correlated Electrons Quantum Physics

Abstract

Kibble-Zurek (KZ) mechanism describes the scaling behavior when driving a system across a continuous symmetry-breaking transition. Previous studies have shown that the KZ-like scaling behavior also lies in the topological transitions in the Qi-Wu-Zhang model (2D) and the Su-Schrieffer-Heeger model (1D), although symmetry breaking does not exist here. Both models with linear band crossings give that ν=1\nu=1 and z=1z=1. We wonder whether different critical exponents can be acquired in topological transitions beyond linear band crossing. In this work, we look into the KZ behavior in a topological 2D checkerboard lattice with a quadratic band crossing. We investigate from dual perspectives: momentum distribution of the Berry curvature in clean systems for simplicity, and real-space analysis of domain-like local Chern marker configurations in disordered systems, which is a more intuitive analog to conventional KZ description. In equilibrium, we find the correlation length diverges with a power ν1/2\nu\simeq 1/2. Then, by slowly quenching the system across the topological phase transition, we find that the freeze-out time tft_\mathrm{f} and the unfrozen length scale ξ(tf)\xi(t_\mathrm{f}) both satisfy the KZ scaling, verifying z2z\simeq 2. We subsequently explore KZ behavior in topological phase transitions with other higher-order band crossing and find the relationship between the critical exponents and the order. Our results extend the understanding of the KZ mechanism and non-equilibrium topological phase transitions.

Keywords

Cite

@article{arxiv.2407.19780,
  title  = {Kibble-Zurek behavior in a topological phase transition with a quadratic band crossing},
  author = {Huan Yuan and Jinyi Zhang and Shuai Chen and Xiaotian Nie},
  journal= {arXiv preprint arXiv:2407.19780},
  year   = {2024}
}

Comments

8 pages, 10 figures