Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Heterostructures, Interfaces and Surfaces
HL 13.6: Vortrag
Montag, 17. März 2025, 18:00–18:15, H17
Topological Phase Diagram of Mercury Cadmium Telluride Quantum Wells — •Leonid Bovkun1,2, Lena Fürst1,2, Christopher Fuchs1,2, Vladimir Marković1,2, Maximilian Hofer1,2, Moritz Siebert1,2, Christian Berger1,2, Florian Bayer1,2, Wouter Beugeling1,2, Steffen Schreyeck1,2, Hartmut Buhmann1,2, Laurens W. Molenkamp1,2, and Tobias Kießling1,2 — 1Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2Institute for Topological Insulators, Am Hubland, 97074 Würzburg, Germany
The key ingredient for the formation of a topological insulator phase in Mercury Cadmium Telluride is the inversion of the energetic positions of the electronic Γ6 and Γ8 bulk bands, that can be controlled by alloying with Cd to get within reach of electronic tunability.
We present a systematic experimental study of the topological phase transition in a series of ∼10 nm thick Hg1−xCdxTe quantum wells by tuning the Cd content x. We provide detailed structural and magneto-optical spectroscopic characterization measurements and establish a comprehensive picture of the alloy structural and energetic properties.
Using these as input, we employ k · p modeling to establish the topological phase diagram of Hg1−xCdxTe in dependence of the Cd content and quantum well thickness for thin films which are pseudomorphically strained to the lattice constant of pure CdTe.
Keywords: Topological insulators; Crystal growth; Magneto-optics; Infrared spectroscopy; Band structure theory