Effect of disorder on 2D topological merging transition from a Dirac semi-metal to a normal insulator
Effect of disorder on 2D topological merging transition from a Dirac semi-metal to a normal insulator
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DOI：
10.1209/0295-5075/102/67010
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
D. Carpentier;A. A. Fedorenko-A.;Edmond Orignac
中科院分区：
文献类型：
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作者：
D. Carpentier;A. A. Fedorenko-A.;Edmond Orignac
我们研究了无序对二维狄拉克半金属到绝缘态拓扑跃迁的影响。这种转变被描述为两个狄拉克点的连续合并，导致在临界点处的半狄拉克谱。后者的特征是在一个方向上呈线性，在正交方向上呈二次分布。使用自洽玻恩近似和重整化群，我们计算了在不同类型的无序存在下的过渡的上方，下方和附近的态密度。除了预期的过渡无序涂抹，我们发现一个中间无序半狄拉克相。在一侧，该相通过连续跃迁与绝缘态分离，而在另一侧，它通过交叉演化到无序狄拉克相。
We study the influence of disorder on the topological transition from a two-dimensional Dirac semi-metal to an insulating state. This transition is described as a continuous merging of two Dirac points leading to a semi-Dirac spectrum at the critical point. The latter is characterized by a dispersion relation linear in one direction and quadratic in the orthogonal one. Using the self-consistent Born approximation and renormalization group we calculate the density of states above, below and in the vicinity of the transition in the presence of different types of disorder. Beyond the expected disorder smearing of the transition we find an intermediate disordered semi-Dirac phase. On one side this phase is separated from the insulating state by a continuous transition while on the other side it evolves through a crossover to the disordered Dirac phase.