Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 29: Quantum Transport and Quantum Hall Effects
HL 29.6: Vortrag
Mittwoch, 20. März 2024, 11:15–11:30, EW 561
In-plane electric-field effects at transitions between quantum Hall plateaus in InAs-based quantum wells — •Olivio Chiatti1, Johannes Boy1, Christian Heyn3, Wolfgang Hansen3, and Saskia F. Fischer1,2 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 10099 Berlin, Germany — 2Center for the Science of Materials Berlin, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — 3Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg, 20148 Hamburg, Germany
The cross-over from quasi-two- to quasi-one-dimensional electron transport is studied in dependence of transverse electric fields and perpendicular magnetic fields, both in the diffusive to quasi-ballistic and in the zero-field to quantum Hall regime. Hall-bars and in-plane gates have been fabricated from an InGaAs/InAlAs/InAs quantum well hosting a 2DEG. Magnetotransport measurements at temperatures down to 50 mK and fields up to 12 T show a high effective Lande-factor of |g*| = 16, allowing to resolve spin-split subbands at magnetic fields of 2.5 T. In the quantum Hall regime, electrostatic change of the effective constriction width enables control of the reflection and transmission of edge channels, allowing to separate fully spin-polarized edge channels at filling factors ν = 1 und ν = 2. A change in the orientation of a transverse in-plane electric field in the constriction shifts the transition between Zeeman-split quantum Hall plateaus by ΔB ≈ 0.1 T and is consistent with an effective magnetic field of Beff ≈ 0.13 T by spin-dependent backscattering, indicating a change in the spin-split density of states.
Keywords: Quantum-Hall effect; edge channels; InAs quantum well; magnetotransport; in-plane gates