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HL: Fachverband Halbleiterphysik

HL 102: Quantum dots and wires: Transport

HL 102.5: Vortrag

Freitag, 15. März 2013, 12:15–12:30, H13

Investigation of Spin-Orbit Coupling in Differently Doped InAs Nanowires — •Sebastian Heedt¹, Thomas Gerster¹, Isabel Wehrmann^1,2, Kamil Sladek¹, Hilde Hardtdegen¹, Detlev Grützmacher¹, and Thomas Schäpers^1,3 — ¹Peter Grünberg Institut (PGI-9) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany — ²OSRAM Opto Semiconductors GmbH, 93055 Regensburg, Germany — ³II. Physikalisches Institut, RWTH Aachen University, 52056 Aachen, Germany

Low-temperature quantum transport is presented for top-gated InAs nanowires prepared by selective area metalorganic vapor phase epitaxy. The carrier concentration and the band profile can be controlled by means of doping or the application of a gate voltage. Phase-coherent transport is investigated for temperatures down to 30 mK and magnetic fields up to 10 T. Utilizing an analytical model for the low-field quantum conductivity correction, we are able to extract the phase coherence length l_φ and the spin relaxation length l_so. The model applies for diffusive wires with diameters falling short of l_φ. It accounts for spin relaxation under linear Rashba and linear and cubic Dresselhaus spin-orbit coupling. To investigate these effects, superimposed universal conductance fluctuations have to be eliminated by averaging magnetic field dependent measurements across a wide gate voltage range. Thus, individual nanowires with different doping concentrations are investigated to gain information on how the doping of the highly spin-orbit coupled InAs nanowires impacts the spin-lifetime.