Even at the lowest accessible temperatures, measurements of the quantum anomalous Hall (QAH) effect have indicated the presence of parasitic dissipative conduction channels. There is no consensus whether parasitic conduction is related to processes in the bulk or along the edges. Here, we approach this problem by comparing transport measurements of Hall bar and Corbino geometry devices fabricated from Cr-doped (BiSb)₂Te₃. We identify bulk conduction as the dominant source of dissipation at all values of temperature and in-plane electric field. Furthermore, we observe identical breakdown phenomenology in both geometries, indicating that breakdown of the QAH phase is a bulk process. The methodology developed in this study could be used to identify dissipative conduction mechanisms in new QAH materials, ultimately guiding material development toward realization of the QAH effect at higher temperatures.

中文翻译：

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量子反常霍尔效应中的体耗散

即使在最低可达温度下，量子反常霍尔 (QAH) 效应的测量也表明存在寄生耗散传导通道。寄生传导是否与本体或沿边缘的过程有关尚无共识。在这里，我们通过比较由 Cr 掺杂 (BiSb) ₂ Te ₃制造的霍尔棒和 Corbino 几何器件的传输测量来解决这个问题. 我们将体传导确定为所有温度和面内电场值下的主要耗散源。此外，我们在两种几何结构中观察到相同的击穿现象，表明 QAH 相的击穿是一个整体过程。本研究中开发的方法可用于确定新 QAH 材料中的耗散传导机制，最终指导材料开发在更高温度下实现 QAH 效应。