@article{1b7d47d41a704422977ff05af58b8460,
title = "Delocalization Transition of a Disordered Axion Insulator",
abstract = "The axion insulator is a higher-order topological insulator protected by inversion symmetry. We show that, under quenched disorder respecting inversion symmetry on average, the topology of the axion insulator stays robust, and an intermediate metallic phase in which states are delocalized is unavoidable at the transition from an axion insulator to a trivial insulator. We derive this conclusion from general arguments, from classical percolation theory, and from the numerical study of a 3D quantum network model simulating a disordered axion insulator through a layer construction. We find the localization length critical exponent near the delocalization transition to be ν=1.42±0.12. We further show that this delocalization transition is stable even to weak breaking of the average inversion symmetry, up to a critical strength. We also quantitatively map our quantum network model to an effective Hamiltonian and we find its low-energy k·p expansion.",
author = "Song, {Zhi Da} and Biao Lian and Raquel Queiroz and Roni Ilan and Bernevig, {B. Andrei} and Ady Stern",
note = "Funding Information: We are grateful to Xiao-Yan Xu and Yuanfeng Xu for useful discussions. B. A. B. and Z.-D. S. were supported by the DOE Award No. DE-SC0016239, the Schmidt Fund for Innovative Research, Simons Investigator Grant No. 404513, and the Packard Foundation. Further support was provided by the NSF-EAGER No. DMR 1643312, NSF-MRSEC No. DMR-1420541, and ONR No. N00014-20-1-2303, and Gordon and Betty Moore Foundation through Grant No. GBMF8685 toward the Princeton theory program. The development of the network model is supported by DOE Award No. DE-SC0016239. R. I. and B. A. B. also acknowledge the support from BSF Israel U.S. foundation No. 2018226. A. S. acknowledges supports from the European Research Council (Project LEGOTOP), the National Science Foundation under Grant No. NSF PHY-1748958, the Israel Science Foundation—Quantum Program, and the RC/Transregio 183 of the Deutsche Forschungsgemeinschaft. Publisher Copyright: {\textcopyright} 2021 American Physical Society.",
year = "2021",
month = jul,
day = "2",
doi = "10.1103/PhysRevLett.127.016602",
language = "English (US)",
volume = "127",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "1",
}