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arXiv · 1208.2741

Topological insulator in a Bi-Bi$_2$Se$_3$ infinitely adaptive superlattice phase

T. Valla·Huiwen Ji·L. M. Schoop·A. P. Weber·Z. -H. Pan·J. T. Sadowski·E. Vescovo·A. V. Fedorov·A. N. Caruso·Q. D. Gibson·L. Muchler·C. Felser·R. J. Cava
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Abstract

We report spin- and angle-resolved photoemission studies of a topological insulator from the infinitely adaptive series between elemental Bi and Bi$_2$Se$_3$. The compound, based on Bi$_4$Se$_3$, is a 1:1 natural superlattice of alternating Bi$_2$ layers and Bi$_2$Se$_3$ layers; the inclusion of S allows the growth of large crystals, with the formula Bi$_4$Se$_{2.6}$S$_{0.4}$. The crystals cleave along the interfaces between the Bi$_2$ and Bi$_2$Se$_3$ layers, with the surfaces obtained having alternating Bi or Se termination. The resulting terraces, observed by photoemission electron microscopy, create avenues suitable for the study of one-dimensional topological physics. The electronic structure, determined by spin- and angle- resolved photoemission spectroscopy, shows the existence of a surface state that forms a large, hexagonally shaped Fermi surface around the $Γ$ point of the surface Brillouin zone, with the spin structure indicating that this material is a topological insulator.

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T. Valla, Huiwen Ji, L. M. Schoop, A. P. Weber, Z. -H. Pan, J. T. Sadowski, E. Vescovo, A. V. Fedorov, A. N. Caruso, Q. D. Gibson, L. Muchler, C. Felser, R. J. Cava. 2013-01-08. Topological insulator in a Bi-Bi$_2$Se$_3$ infinitely adaptive superlattice phase. https://doi.org/10.1103/physrevb.86.241101

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