Monopole charge density wave states in Weyl semimetals
Monopole charge density wave states in Weyl semimetals
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DOI：
10.1103/physrevresearch.2.012078
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发表时间：
2018-10
影响因子：
4.2
通讯作者：
Eric Bobrow;Canon Sun;Y. Li
中科院分区：
文献类型：
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作者：
Eric Bobrow;Canon Sun;Y. Li
我们研究了一类新的拓扑电荷密度波态，表现出单极谐波对称性。由于相互作用下的费米表面嵌套，密度波排序相当于粒子空穴通道中的配对。当电子和空穴费米表面携带不同的陈数时，粒子-空穴配对表现出继承自能带结构拓扑的非平凡贝里相，与具体的密度波排序机制无关。相关的密度波隙函数变成节点函数，净节点涡度由配对贝里相的单极子电荷决定。间隙函数节点成为准粒子激发体光谱的零能量 Weyl 节点。这些状态可以出现在具有嵌套电子和空穴费米表面的掺杂外尔半金属中，其在弱耦合状态下包围相同手性的外尔节点。由于零能量韦尔节点的出现，拓扑上非平凡的低能费米弧表面态出现在密度波有序态中。
We study a new class of topological charge density wave states exhibiting monopole harmonic symmetries. The density-wave ordering is equivalent to pairing in the particle-hole channel due to Fermi surface nesting under interactions. When electron and hole Fermi surfaces carry different Chern numbers, the particle-hole pairing exhibits a non-trivial Berry phase inherited from band structure topology independent of concrete density-wave ordering mechanism. The associated density-wave gap functions become nodal, and the net nodal vorticity is determined by the monopole charge of the pairing Berry phase. The gap function nodes become zero-energy Weyl nodes of the bulk spectra of quasi-particle excitations. These states can occur in doped Weyl semimetals with nested electron and hole Fermi surfaces enclosing Weyl nodes of the same chirality in the weak coupling regime. Topologically non-trivial low-energy Fermi arc surface states appear in the density-wave ordering state as a consequence of the emergent zero-energy Weyl nodes.