Direct observation and temperature control of the surface Dirac gap in a topological crystalline insulator
| Autor: | B. M. Wojek, Viktor Jonsson, Oscar Tjernberg, Bogdan J. Kowalski, Tomasz Story, M. H. Berntsen, Andrzej Szczerbakow, Piotr Dziawa |
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| Rok vydání: | 2015 |
| Předmět: |
Physics
Multidisciplinary Topological degeneracy General Physics and Astronomy General Chemistry Topology Symmetry protected topological order Article General Biochemistry Genetics and Molecular Biology Massless particle Topological insulator Homogeneous space Topological order Phase diagram Surface states |
| Zdroj: | Nature Communications |
| ISSN: | 2041-1723 |
| DOI: | 10.1038/ncomms9463 |
| Popis: | Since the advent of topological insulators hosting Dirac surface states, efforts have been made to gap these states in a controllable way. A new route to accomplish this was opened up by the discovery of topological crystalline insulators where the topological states are protected by crystal symmetries and thus prone to gap formation by structural changes of the lattice. Here we show a temperature-driven gap opening in Dirac surface states within the topological crystalline insulator phase in (Pb,Sn)Se. By using angle-resolved photoelectron spectroscopy, the gap formation and mass acquisition is studied as a function of composition and temperature. The resulting observations lead to the addition of a temperature- and composition-dependent boundary between massless and massive Dirac states in the topological phase diagram for (Pb,Sn)Se (001). Overall, our results experimentally establish the possibility to tune between massless and massive topological states on the surface of a topological system. The opening of a Dirac point gap in topologically non-trivial materials is key to potential applications. Here, the authors use photoelectron spectroscopy to study gap formation and carrier mass acquisition in a topological crystalline insulator as a function of composition and temperature. |
| Databáze: | OpenAIRE |
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