Tilted disordered Weyl semimetals
Tilted disordered Weyl semimetals
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DOI：
10.1103/physrevb.95.045139
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发表时间：
2016-11
影响因子：
3.7
通讯作者：
Maximilian Trescher;B. Sbierski;P. Brouwer;E. Bergholtz
中科院分区：
文献类型：
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作者：
Maximilian Trescher;B. Sbierski;P. Brouwer;E. Bergholtz
虽然洛伦兹不变性禁止外尔哈密顿量中存在一个使能量-动量关系倾斜的项，但倾斜色散并不被禁止，事实上，这对于外尔半金属的凝聚态实现是通用的。在这里，我们调查这样一个倾斜的外尔分散体和潜在的障碍的存在下的综合效果。特别是，我们解决的倾斜的影响，在弱无序，其中的障碍是一个无关的扰动，和扩散相在强无序的准弹道相之间的无序诱导的相变。我们的主要结果是，倾斜的存在下，导致这种转变的临界无序强度的减少，或者等价地，在固定的无序强度增加倾斜驱动系统通过相变的扩散强无序相。值得注意的是，这掩盖了倾斜诱导的Lifshitz过渡到过度倾斜的II型外尔相在任何有限的无序强度。我们的结果得到了使用自洽玻恩近似的分析计算以及态密度和输运性质的数值计算的支持。
Although Lorentz invariance forbids the presence of a term that tilts the energy-momentum relation in the Weyl Hamiltonian, a tilted dispersion is not forbidden and, in fact, generic for condensed matter realizations of Weyl semimetals. We here investigate the combined effect of such a tilted Weyl dispersion and the presence of potential disorder. In particular, we address the influence of a tilt on the disorder-induced phase transition between a quasiballistic phase at weak disorder, in which the disorder is an irrelevant perturbation, and a diffusive phase at strong disorder. Our main result is that the presence of a tilt leads to a reduction of the critical disorder strength for this transition or, equivalently, that increasing the tilt at fixed disorder strength drives the system through the phase transition to the diffusive strong-disorder phase. Notably this obscures the tilt-induced Lifshitz transition to an overtilted type II Weyl phase at any finite disorder strength. Our results are supported by analytical calculations using the self-consistent Born approximation and numerical calculations of the density of states and of transport properties.