Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 63: Poster: Quantum Dots and Optics
HL 63.75: Poster
Mittwoch, 22. März 2017, 15:00–19:00, P1A
Magnetotransport in narrow-gap semiconductor nanostructures — •Johannes Boy1, Olivio Chiatti1, Christian Heyn2, Wolfgang Hansen2, and Saskia F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — 2Institut für Angewandte Physik, Universität Hamburg, 20355 Hamburg, Germany
The Shubnikov de-Haas effect is a powerful tool to determine the electric transport parameters of a two-dimensional electrongas (2DEG).
Our experimental work has been directed at the magnetotransport under the influence of in-plane gates. We have combined quantum point contacts (QPCs) with in-plane gates and Hall-bars (HB) in a narrow-gap semiconductor heterostructure with strong spin-orbit interaction. The investigated structures were fabricated by micro-laser photolithography and wet-chemical etching from an InGaAs/InAlAs/InAs quantum well [1]. The 2DEG has carrier densities of about 6.7·1011 cm−2, mobilities of 0.8 − 1.8·105 cm2/Vs and an effective mass of 0.042 · me after illumination. We have performed magnetotransport measurements at temperatures down to 250 mK. Hall-bar structures were investigated in tilted magnetic fields up to 10 T. Combined QPC and HB structures were studied using various gate voltages in perpendicular magnetic fields up to 10 T. We determined the effective Lande-factor g*=16 and the Landau-level broadening Γ=2.2 meV. We observed the transition of reflection of the quantum Hall edge channels at the QPC to transmission by changing the gate voltage.
[1] Chiatti et al., Appl. Phys. Lett. 106, 052102 (2015).