Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 14: Poster: Two-Dimenaional Materials and Topological Insulators

HL 14.16: Poster

Montag, 20. März 2017, 14:00–18:00, P2-OG3

Growth and transport measurements of gapless HgCdTe. — •Raimund Schlereth, Christoph Brüne, Hartmut Buhmann, and Laurens Molenkamp — Universität Würzburg, EP3

Three dimensional gapless semiconductors show promising new transport phenomena, due to their linear dispersion in all three momentum directions.

In this work we focus on HgTe/CdTe based compounds which crystalize in a zinc blende structure. Tensile strained HgTe is a three dimensional topological insulator [1] with an inverted band structure where the Γ8-bands lie above the Γ6-band. To get a linear dispersion, the band gap of the HgTe needs to be closed. Hg and Cd substitute each other in alloys of HgCdTe nearly randomly, making any Hg/Cd ratio possible. Therefore we can adjust the band structure in such a way, that the Γ8-band touches the Γ6-band, creating a linear dispersion. This linear dispersion however is not protected by symmetry or topology, but is achieved by fine-tuning of a system parameter (Hg/Cd ratio) [2]. We present magnetic field and gate voltage dependent transport data of HgCdTe with varying Hg concentration around the transitional point from the Cd rich to the Hg rich band structure.