Functionalized germanene as a prototype of large-gap two-dimensional topological insulators
By Chen Si, Junwei Liu, Yong Xu, Jian Wu, B. Gu, Wenhui Duan. 2014
184 citations recorded by the source corpus.
We propose two-dimensional (2D) topological insulators (TIs) in functionalized germanenes (GeX, X$\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}$H, F, Cl, Br, or I) using first-principles calculations. We find GeI is a 2D TI with a bulk gap of about 0.3 eV, while GeH, GeF, GeCl, and GeBr can be transformed into TIs with sizable gaps under achievable tensile strains. A unique mechanism is revealed to be responsible for the large topologically nontrivial gap obtained: due to the functionalization, the $\ensuremath{\sigma}$ orbitals with stronger spin-orbit coupling (SOC) dominate the states around the Fermi level, instead of original $\ensuremath{\pi}$ orbitals with weaker SOC. Thereinto, the coupling of the ${p}_{xy}$ orbitals of Ge and heavy halogens in forming the $\ensuremath{\sigma}$ orbitals also plays a key role in the further enlargement of the gaps in halogenated germanenes. Our results suggest a realistic possibility for the utilization of topological effects at room temperature.
Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/02145d188f7f3a05a08d92d43eda7153170b97fc
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In Atomic and Molecular Physics, and Optics
In Materials Chemistry
Citations in the corpus
- Colloquium : Topological band theory (2016, background): “PbX (X=H, F, Cl, Br, I) is predicted to be a 2D TI, but phonon calculations suggest that the structure is not stable.(Si et al. 2014) A study of band topology and stability of the multilayer stanane indicates that one to three layer thick films are TIs, and films with greater thickness are metallic.”
- Evidence for Topological Edge States in a Large Energy Gap near the Step Edges on the Surface of ZrTe 5 (2016, background): “ [1,2]. These exotic properties have been inducing fantastic reveries in electronic device applications. Although considerable theoretical efforts have predicted many 2D TI candidates in recent years [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17], only a few systems, such as the quantum wells”