Classification of stable three-dimensional Dirac semimetals with nontrivial topology
Classification of stable three-dimensional Dirac semimetals with nontrivial topology
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DOI：
10.1038/ncomms5898
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发表时间：
2014-09-01
影响因子：
16.6
通讯作者：
Nagaosa, Naoto
中科院分区：
文献类型：
--
作者：
Yang, Bohm-Jung;Nagaosa, Naoto
三维 (3D) 狄拉克半金属 (SM) 是石墨烯的 3D 类似物，在费米点周围具有线性能量色散。由于电子波函数的非平凡拓扑，3D Dirac SM 显示出非平凡的物理性质，并在适当的外部条件下具有各种奇异的量子态，例如 Weyl SM 和拓扑绝缘体。理论上提出了几种狄拉克 SM，并通过部分实验得到了证实，但其统一的图景仍然缺失。在这里，我们提出了一个通用框架，用于对具有时间反转、反演和单轴旋转对称性的系统中的稳定 3D Dirac SM 进行分类。我们证明了 3D Dirac SM 有两种不同的类别。在一类中，狄拉克 SM 在旋转轴上具有时间反转不变动量的单个狄拉克点 (DP)。而另一类狄拉克 SM 具有一对通过能带反转创建的 DP，并带有量化拓扑不变量。
A three-dimensional (3D) Dirac semimetal (SM) is the 3D analogue of graphene having linear energy dispersion around Fermi points. Owing to the nontrivial topology of electronic wave functions, the 3D Dirac SM shows nontrivial physical properties and hosts various exotic quantum states such as Weyl SMs and topological insulators under proper external conditions. There are several kinds of Dirac SMs proposed theoretically and partly confirmed experimentally, but its unified picture is still missing. Here we propose a general framework to classify stable 3D Dirac SMs in systems having the time-reversal, inversion and uniaxial rotational symmetries. We show that there are two distinct classes of 3D Dirac SMs. In one class, the Dirac SM possesses a single Dirac point (DP) at a time-reversal invariant momentum on the rotation axis. Whereas the other class of Dirac SMs have a pair of DPs created by band inversion, and carry a quantized topological invariant.