Phase diagrams of disordered Weyl semimetals
Phase diagrams of disordered Weyl semimetals
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DOI：
10.1103/physrevb.93.075108
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发表时间：
2015-09
影响因子：
3.7
通讯作者：
Hassan Shapourian;T. Hughes
中科院分区：
文献类型：
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作者：
Hassan Shapourian;T. Hughes
韦尔半金属是无隙准拓扑材料，具有一组形成费米面的孤立节点。它们通过一系列拓扑电磁响应（包括反常霍尔效应）表现出其准拓扑特征。在这里，我们研究无序对外尔半金属的影响，同时通过计算局域长度和霍尔电导率来监测它们的节点/半金属和拓扑特性。我们研究了三种不同的晶格紧束缚模型，它们在相图中部分实现了外尔半金属，并寻找所有模型共有的通用特征，以及每个模型有趣的区别特征。我们展示了这些模型针对大系统尺寸的详细相图，我们发现弱无序将节点保留到扩散极限，但确实影响霍尔电导率。我们表明，霍尔电导率的趋势与有效图像一致，其中无序导致外尔节点在布里渊区内沿着特定方向移动，该方向决定性地取决于模型的性质以及外尔半金属相的相邻相。我们还发现了一种不寻常的（非量子化的）反常霍尔绝缘体相，它只能在存在无序的情况下存在。
Weyl semimetals are gapless quasi-topological materials with a set of isolated nodal points forming their Fermi surface. They manifest their quasi-topological character in a series of topological electromagnetic responses including the anomalous Hall effect. Here we study the effect of disorder on Weyl semimetals while monitoring both their nodal/semi-metallic and topological properties through computations of the localization length and the Hall conductivity. We examine three different lattice tight-binding models which realize the Weyl semimetal in part of their phase diagram and look for universal features that are common to all of the models, and interesting distinguishing features of each model. We present detailed phase diagrams of these models for large system sizes and we find that weak disorder preserves the nodal points up to the diffusive limit, but does affect the Hall conductivity. We show that the trend of the Hall conductivity is consistent with an effective picture in which disorder causes the Weyl nodes move within the Brillouin zone along a specific direction that depends deterministically on the properties of the model and the neighboring phases to the Weyl semimetal phase. We also uncover an unusual (non-quantized) anomalous Hall insulator phase which can only exist in the presence of disorder.