Evidence for topological band inversion of the phase change material Ge2Sb2Te5
| Autor: | Marcus Liebmann, E. D. L. Rienks, Jens Kellner, Jaime Sánchez-Barriga, Raffaella Calarco, Markus Morgenstern, Sven Just, Christian Pauly, Gustav Bihlmayer, Oliver Rader, Alessandro Giussani |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Condensed Matter - Materials Science
Materials science Physics and Astronomy (miscellaneous) Condensed Matter - Mesoscale and Nanoscale Physics Band gap business.industry Astrophysics::High Energy Astrophysical Phenomena Fermi level Scanning tunneling spectroscopy Stacking Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Topology symbols.namesake Semiconductor Metastability Mesoscale and Nanoscale Physics (cond-mat.mes-hall) symbols Density functional theory ddc:530 Condensed Matter::Strongly Correlated Electrons business Surface states |
| Zdroj: | Applied physics letters 103(24), 243109 (2013). doi:10.1063/1.4847715 |
| Popis: | We present an angle-resolved photoemission study of a ternary phase change material, namely Ge2Sb2Te5, epitaxially grown on Si(111) in the metastable cubic phase. The observed upper bulk valence band shows a minimum at Gamma-bar being 0.3 eV below the Fermi level E_F and a circular Fermi contour around Gamma-bar with a dispersing diameter of 0.27-0.36 Anstroms^-1. This is in agreement with density functional theory calculations of the Petrov stacking sequence in the cubic phase which exhibits a topological surface state. The topologically trivial cubic KH stacking shows a valence band maximum at Gamma in line with all previous calculations of the hexagonal stable phase exhibiting the valence band maximum at Gamma for a trivial Z_2 topological invariant nu_0 and away from Gamma for non-trivial nu_0. Scanning tunneling spectroscopy exhibits a band gap of 0.4 eV around E_F. |
| Databáze: | OpenAIRE |
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