Fulga I C, Oreg Yuval, Mirlin Alexander D, Stern Ady, Mross David F
IFW Dresden and Würzburg-Dresden Cluster of Excellence, Helmholtzstrasse 20, 01069 Dresden, Germany.
Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Phys Rev Lett. 2020 Dec 4;125(23):236802. doi: 10.1103/PhysRevLett.125.236802.
The quest for non-Abelian quasiparticles has inspired decades of experimental and theoretical efforts, where the scarcity of direct probes poses a key challenge. Among their clearest signatures is a thermal Hall conductance with quantized half-integer value in units of κ_{0}=π^{2}k_{B}^{2}T/3h (T is temperature, h the Planck constant, k_{B} the Boltzmann constant). Such values were recently observed in a quantum-Hall system and a magnetic insulator. We show that nontopological "thermal metal" phases that form due to quenched disorder may disguise as non-Abelian phases by well approximating the trademark quantized thermal Hall response. Remarkably, the quantization here improves with temperature, in contrast to fully gapped systems. We provide numerical evidence for this effect and discuss its possible implications for the aforementioned experiments.
对非阿贝尔任意子的探索激发了数十年来的实验和理论研究工作，而直接探测手段的匮乏构成了一项关键挑战。它们最明显的特征之一是热霍尔电导，其量子化的半整数值以κ₀ = π²k₈²T/3h为单位（T为温度，h为普朗克常数，k₈为玻尔兹曼常数）。最近在一个量子霍尔系统和一种磁性绝缘体中观察到了这样的值。我们表明，由于淬火无序而形成的非拓扑“热金属”相可能通过很好地近似标志性的量子化热霍尔响应而伪装成非阿贝尔相。值得注意的是，与完全能隙系统相反，这里的量子化随温度而改善。我们为这种效应提供了数值证据，并讨论了其对上述实验可能产生的影响。
