000217749 001__ 217749
000217749 005__ 20190121170015.0
000217749 0247_ $$2doi$$a10.1038/srep20220
000217749 022__ $$a2045-2322
000217749 02470 $$2ISI$$a000369384400001
000217749 037__ $$aARTICLE
000217749 245__ $$aDirac fermions at high-index surfaces of bismuth chalcogenide topological insulator nanostructures
000217749 260__ $$aLondon$$bNature Publishing Group$$c2016
000217749 269__ $$a2016
000217749 300__ $$a9
000217749 336__ $$aJournal Articles
000217749 520__ $$aBinary bismuth chalcogenides Bi2Se3, Bi2Te3, and related materials are currently being extensively investigated as the reference topological insulators (TIs) due to their simple surface-state band dispersion (single Dirac cone) and relatively large bulk band gaps. Nanostructures of TIs are of particular interest as an increased surface-to-volume ratio enhances the contribution of surfaces states, meaning they are promising candidates for potential device applications. So far, the vast majority of research efforts have focused on the low-energy (0001) surfaces, which correspond to natural cleavage planes in these layered materials. However, the surfaces of low-dimensional nanostructures (nanoplatelets, nanowires, nanoribbons) inevitably involve higher-index facets. We perform a systematic ab initio investigation of the surfaces of bismuth chalcogenide TI nanostructures characterized by different crystallographic orientations, atomic structures and stoichiometric compositions. We find several stable terminations of high-index surfaces, which can be realized at different values of the chemical potential of one of the constituent elements. For the uniquely defined stoichiometric termination, the topological Dirac fermion states are shown to be strongly anisotropic with a clear dependence of Fermi velocities and spin polarization on the surface orientation. Self-doping effects and the presence of topologically trivial mid-gap states are found to characterize the non-stoichiometric surfaces. The results of our study pave the way towards experimental control of topologically protected surface states in bismuth chalcogenide nanostructures.
000217749 700__ $$0246469$$aVirk, Naunidh$$g218550
000217749 700__ $$0241027$$aYazyev, Oleg V.$$g161849
000217749 773__ $$j6$$q20220$$tScientific Reports
000217749 909C0 $$0252458$$pC3MP$$xU12491
000217749 909CO $$ooai:infoscience.tind.io:217749$$pSB$$particle
000217749 937__ $$aEPFL-ARTICLE-217749
000217749 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000217749 980__ $$aARTICLE