Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 22: Quantum dots and wires: Transport properties
HL 22.1: Vortrag
Dienstag, 2. April 2019, 14:00–14:15, H34
Influence of the Current Density on Universal Conductance Fluctuations in GaN Nanowires — •Patrick Uredat1,2, Pascal Hille1,2, Jörg Schörmann1,2, Martin Eickhoff3, Matthias T. Elm1,2, and Peter J. Klar1,2 — 1Center for Materials Research, Justus Liebig University, 35392 Giessen, Germany — 2Institute for Experimental Physics I, Justus Liebig University, 35392 Giessen, Germany — 3Institute of Solid State Physics, University of Bremen, 28359 Bremen, Germany
We present investigations of the magnetotransport properties of single Ge-doped GaN nanowires grown by molecular-beam epitaxy which exhibit quantum-interference effects at low temperatures. By analyzing the emerging quantum-interference effects the phase-coherence length can be determined in different ways, i.e. based on universal conductance fluctuations (UCF) and weak localization effects. As the phase-coherence length is solely defined by inelastic scattering events the phase-coherence is independent of the current applied. Nevertheless, we show, that the magnitude of the conductance fluctuations rms(ΔG) is strongly affected by the applied current density resulting in an alleged reduction of the obtained phase-coherence length. The decrease of the magnitude rms(ΔG) with increasing current density occurs due to more k-states close to the Fermi energy contributing to the transport which smears out the UCF. We provide a theoretical model to describe the influence of applied current density on the UCF which furthermore enables us to obtain the carrier concentration and carrier mobility of a single Ge-doped GaN nanowires.