Anderson Critical Metal Phase in Trivial States Protected by $C_{2z}T$ Symmetry on Average

Author:

Fa-Jie Wang, Zhen-Yu Xiao, Raquel Queiroz, B. Andrei Bernevig, Ady Stern, Zhi-Da Song

Keyword:

Condensed Matter, Disordered Systems and Neural Networks, Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

journal:

date:

2023-06-06 16:00:00

Abstract

The joint symmetry $C_{2z}T$ protects obstructed atomic insulators in 2D translational invariant magnetic materials, where electrons form molecule orbitals with charge centers away from the positions of atoms. The transitions from these states to atomic insulators have to go through an intermediate metallic phase accomplished by the emergence, evolution, and annihilation of Dirac points. We show that, under (quenched) weak chemical potential disorder that respects the $C_{2z}T$ symmetry on average, the intermediate metallic phase remains delocalized, where every point in a finite transition process is a scale-invariant critical metal in the thermodynamic limit. We thus refer to the delocalized metallic phase as a crystalline-symmetry-associated critical metal phase. The underlying mechanism cannot be explained by conventional localization theories, such as weak anti-localization and topological phase transition in the ten-fold way classification. Through a quantitative mapping between lattice models and network models, we find that the critical metal phase is equivalent to a quantum percolation problem with random fluxes. The criticality can hence be understood through a semi-classical percolation theory.

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