Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 95: Poster IV B (Quantum dots and wires: Prepration, characterization, optical properties, and transport)
HL 95.30: Poster
Donnerstag, 19. März 2015, 14:00–20:00, Poster B
Narrow-gap semiconductor nanstructures in the quantum Hall regime — •Olivio Chiatti1, Chistian Riha1, Johannes Boy1, Christian Heyn2, Wolfgang Hansen2, and Saskia F. Fischer1 — 1Neue Materialien, Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — 2Institut für Angewandte Physik, Universität Hamburg, 20148 Hamburg, Germany
One of the most prominent phenomena in modern solid state physics is the quantum Hall effect (QHE). The quantum Hall edge channels (QHECs) are central to our understanding of the underlying physics of the QHE. Most research has been directed at GaAs/AlGaAs heterostructure systems, but there has been little work directed at understanding the role of spin-orbit interaction (SOI) in this phenomenon.
We have combined quantum point contacts (QPCs) with in-plane gates and Hall-bars in a narrow-gap semiconductor heterostructure with strong SOI. The constriction was fabricated by micro-laser photolithography and wet-chemical etching from an InGaAs/InAlAs quantum well with an InAs-inserted channel [1]. The two-dimensional electron gas (2DEG) is at about 53 nm depth and has a carrier density of about 3·1011 cm−2 and mobility of about 7.5·104 cm2/Vs, in the dark.
We have performed transport measurements of the combined QPC and Hall-bar structures in magnetic fields perpendicular to the 2DEG. We observe conductance quantization through the QPC when QHECs are formed. We discuss the transmission and reflection of QHECs as a function of symmetric and asymmetric in-plane gate voltages.
[1] Chiatti et al., arXiv:1410.8588v2 [cond-mat.mes-hall] (2014).