Exotic topological insulator states and topological phase transitions in Sb2Se3-Bi2Se3 heterostructures
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
Computational Physics and Materials Science (CPMS)
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AbstractTopological insulator is a new state of matter attracting tremendous interest due to its gapless linear dispersion and spin momentum locking topological states located near the surface. Heterostructures, which have traditionally been powerful in controlling the electronic properties of semiconductor devices, are interesting for topological insulators. Here, we studied the spatial distribution of the topological state in Sb 2Se 3-Bi 2Se 3 heterostructures by first-principle simulation and discovered that an exotic topological state exists. Surprisingly, the state migrates from the nontrivial Bi 2Se 3 into the trivial Sb 2Se 3 region and spreads across the entire Sb 2Se 3 slab, extending beyond the concept of "surface" state while preserving all of the topological surface state characteristics. This unusual topological state arises from the coupling between different materials and the modification of electronic structure near Fermi energy. Our study demonstrates that heterostructures can open up opportunities for controlling the real-space distribution of the topological state and inducing quantum phase transitions between topologically trivial and nontrivial states. © 2012 American Chemical Society.
SponsorsY.C. acknowledges the support from the Keck Foundation, DARPA MESO project (No. N66001-11-1-4105) and King Abdullah University of Science and Technology (KAUST) Investigator Award (No. KUS-I1-001-12). The authors acknowledge the National Energy Research Scientific Computing Center (NERSC) and KAUST for computer time. Z.Z. acknowledges partial support from National Nanotechnology Infrastructure Network (NNIN).
PublisherAmerican Chemical Society (ACS)