Spin valleytronics in silicene: Quantum spin Hall–quantum anomalous Hall insulators and single-valley semimetals
By M. Ezawa. 2013
235 citations recorded by the source corpus.
Valley-based electronics, known as valleytronics, is one of the keys to breaking through to a new stage of electronics. The valley degree of freedom is ubiquitous in the honeycomb lattice system. The honeycomb lattice structure of silicon, called silicene, is a fascinating playground of valleytronics. We investigate topological phases of silicene by introducing different exchange fields on the $A$ and $B$ sites. There emerges a rich variety of topologically protected states, each of which has a characteristic spin-valley structure. The single Dirac-cone semimetal is such a state where one gap is closed while the other three gaps are open, evading the Nielsen-Ninomiya fermion-doubling problem. We have newly discovered a hybrid topological insulator named the quantum spin\char21{}quantum anomalous Hall insulator, where the quantum anomalous Hall effect occurs at one valley and the quantum spin Hall effect occurs at the other valley. Along its phase boundary, single-valley semimetals emerge, where only one of the two valleys is gapless with degenerated spins. These semimetals are also topologically protected because they appear in the interface of different topological insulators. Such a spin-valley-dependent physics will be observed by optical absorption or edge modes.
Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/5d8f3e0079e45c5a97dca5d128c48a45b7c4bb55
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In Atomic and Molecular Physics, and Optics
In Materials Chemistry
Citations in the corpus
- Quantum anomalous Hall effect and related topological electronic states (2015, background): “r in manganese chalcogenophosphates was recently discussed [203]. We observe that the conguration of Berry curvature given in Fig.22(e) corresponds to an additional topological state [161] (see also [204]), by ipping the sign of the Berry curvature around K0valley in the spin up channel from the CDW”