Observation of Topological Crystalline Insulator phase in the lead tin chalcogenide Pb1-xSnxTe material class

Su-Yang Xu; Chang Liu; N. Alidoust; D. Qian; M. Neupane; J. D. Denlinger; Y. J. Wang; L. A. Wray; R. J. Cava; H. Lin; A. Marcinkova; E. Morosan; A. Bansil; M. Z. Hasan

arXiv · 1206.2088

Observation of Topological Crystalline Insulator phase in the lead tin chalcogenide Pb1-xSnxTe material class

Su-Yang Xu·Chang Liu·N. Alidoust·D. Qian·M. Neupane·J. D. Denlinger·Y. J. Wang·L. A. Wray·R. J. Cava·H. Lin·A. Marcinkova·E. Morosan·A. Bansil·M. Z. Hasan

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Abstract

We perform systematic angle-resolved photoemission spectroscopic measurements on the lead tin telluride Pb1-xSnxTe pseudobinary alloy system. We show that the (001) crystalline surface, which is a crystalline surface symmetric about the (110) mirror planes of the Pb1-xSnxTe crystal, pos- sesses four metallic surface states within its surface Brillouin zone. Our systematic Fermi surface and band topology measurements show that the observed Dirac-like surface states lie on the symmetric momentum-space cuts. We further show that upon going to higher electron binding energies, the surface states' isoenergetic countours in close vicinity of each X point are observed to hybridize with each other, leading to a Fermi surface fractionalization and the Lifshitz transition. In addition, systematic incident photon energy dependent measurements are performed, which enable us to un- ambiguously identify the surface states from the bulk bands. These systematic measurements of the surface and bulk electronic structure on Pb1-xSnxTe, supported by our first principles calculation results, for the first time, show that the Pb1-xSnxTe system belongs to the topological crystalline insulator phase due to the four band inversions at the L points in its Brillouin zone, which has been recently theoretically predicted.

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Su-Yang Xu, Chang Liu, N. Alidoust, D. Qian, M. Neupane, J. D. Denlinger, Y. J. Wang, L. A. Wray, R. J. Cava, H. Lin, A. Marcinkova, E. Morosan, A. Bansil, M. Z. Hasan. 2012-06-11. Observation of Topological Crystalline Insulator phase in the lead tin chalcogenide Pb1-xSnxTe material class. https://arxiv.org/abs/1206.2088

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