Quantum criticality of topological phase transitions in three-dimensional interacting electronic systems
Quantum criticality of topological phase transitions in three-dimensional interacting electronic systems
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DOI：
10.1038/nphys3060
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发表时间：
2014-06
期刊：
影响因子：
19.6
通讯作者：
Bohm-Jung Yang;E. Moon;H. Isobe;N. Nagaosa
中科院分区：
文献类型：
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作者：
Bohm-Jung Yang;E. Moon;H. Isobe;N. Nagaosa
凝聚态系统中的拓扑相变伴随着电子波函数的出现奇点，通常表现为动量空间中的闭合点。在三维的传统拓扑绝缘体中，闭合点附近的低能理论可以用相对论性狄拉克费米子与远距离库仑相互作用耦合来描述；因此，拓扑相变的量子临界点为测试量子电动力学的有趣预测提供了一个有前途的平台。在此，我们发现了拓扑材料中的一类量子临界现象，其反演对称性或时间反转对称性都可以被打破。在量子临界点，新出现的低能费米子，被称为各向异性Weyl费米子，同时表现出相对论和牛顿动力学。各向异性色散与库仑相互作用之间的相互作用导致了一种不同于传统金属中的托马斯-费米屏蔽和狄拉克费米子中的对数屏蔽的屏蔽现象。
Topological phase transitions in condensed matter systems accompany emerging singularities of the electronic wavefunction, often manifested by gap-closing points in momentum space. In conventional topological insulators in three dimensions, the low-energy theory near the gap-closing point can be described by relativistic Dirac fermions coupled to the long-range Coulomb interaction; hence, the quantum critical point of topological phase transitions provides a promising platform to test the intriguing predictions of quantum electrodynamics. Here we discover a class of quantum critical phenomena in topological materials for which either the inversion symmetry or time-reversal symmetry can be broken. At the quantum critical point, the emerging low-energy fermions, dubbed the anisotropic Weyl fermions, show both relativistic and Newtonian dynamics simultaneously. The interplay between the anisotropic dispersion and the Coulomb interaction brings about a screening phenomenon distinct from the conventional Thomas–Fermi screening in metals and logarithmic screening in Dirac fermions.