论文标题
基于SB_2TE_3中的严重DIRAC质量间隙抑制
Severe Dirac Mass Gap Suppression in Sb_2Te_3-based Quantum Anomalous Hall Materials
论文作者
论文摘要
当拓扑表面状态（SS）频谱中开放时，量子异常的大厅（QAH）效应出现在铁磁拓扑绝缘子（FMTI）中。尽管平均质量间隙可能超过28 MeV（或〜320 K），但QAH效应通常只能在低于1 K的温度下检测到QAH效应。我们使用原子分辨率Landau级别的光谱成像，我们比较了原型的fmti fmti fmti fmti fmti fmti cr_0.08（bi_0.08（bi_0.1.1sb_1sb_1.1.92）的电子结构（BI_0.1SB_0.9）_2TE_3，探索原因。在（BI_0.1SB_0.9）_2TE_3中，我们发现了狄拉克能量的空间随机变化。在CR_0.08（BI_0.1SB_0.9）中检测到统计上等效的DIRAC能量变化_1.92Te_3，具有并发但不相关的DIRAC质量间隙障碍。对于纳米级区域，这两类SS电子疾病共同抑制低于100μEV的最小质量间隙，分别为<1μm。这从根本上限制了基于SB_2TE_3的FMTI材料中完全量化的异常霍尔效应到非常低的温度。
Quantum anomalous Hall (QAH) effect appears in ferromagnetic topological insulators (FMTI) when a Dirac mass gap opens in the spectrum of the topological surface states (SS). Unaccountably, although the mean mass gap can exceed 28 meV (or ~320 K), the QAH effect is frequently only detectable at temperatures below 1 K. Using atomic-resolution Landau level spectroscopic imaging, we compare the electronic structure of the archetypal FMTI Cr_0.08(Bi_0.1Sb_0.9)_1.92Te_3 to that of its non-magnetic parent (Bi_0.1Sb_0.9)_2Te_3, to explore the cause. In (Bi_0.1Sb_0.9)_2Te_3, we find spatially random variations of the Dirac energy. Statistically equivalent Dirac energy variations are detected in Cr_0.08(Bi_0.1Sb_0.9)_1.92Te_3 with concurrent but uncorrelated Dirac mass gap disorder. These two classes of SS electronic disorder conspire to drastically suppress the minimum mass gap to below 100 μeV for nanoscale regions separated by <1 μm. This fundamentally limits the fully quantized anomalous Hall effect in Sb_2Te_3-based FMTI materials to very low temperatures.
