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Topological phase transition and two dimensional topological insulators in Ge-based thin films
We discuss possible topological phase transitions in Ge-based thin films of
Ge(BiSb)Te as a function of layer thickness and Bi
concentration using the first principles density functional theory
framework. The bulk material is a topological insulator at = 1.0 with a
single Dirac cone surface state at the surface Brillouin zone center, whereas
it is a trivial insulator at = 0. Through a systematic examination of the
band topologies we predict that thin films of Ge(BiSb)Te
with = 0.6, 0.8 and 1.0 are candidates for two-dimensional (2D) topological
insulators, which would undergo a 2D topological phase transition as a function
of . A topological phase diagram for Ge(BiSb)Te thin
films is presented to help guide their experimental exploration.Comment: 7 pages, 5 figures, Accepted for publication in Physical Review B
(2012
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