Workshop book - Physikzentrum der RWTH Aachen - RWTH Aachen ...

Posters Monday February 4
Poster 19:
Quantized conductance in InSb nanowires and electrical characterization of
branched InSb nanowires
Ilse van Weperen
Indium antimonide (InSb) nanowires have shown potential for creation of
topological superconducting and helical liquid states. We report on transport
measurements of single high-mobility indium antimonide nanowires and
branched InSb nanowires.
A novel growth mechanism allows two InSb nanowires to merge into a nano-
T or nanocross. Transport measurements of branched nanowires show characteristics
similar to that of single nanowires. Magnetoresistance measurements
of nanocrosses allow extraction of nanowire electron density.
A mean free path of ∼ 300 nm in InSb nanowires enables observation of
one-dimensional conductance channels at high (B > 2 T) magnetic fields.
Conductance quantization is studied as a function of magnetic field and bias
voltage, enabling extraction of an effective g-factor of ∼ 65 and a subband
spacing of ∼ 15 meV.
Poster 20:
Phase-Coherent Transport and Spin-Orbit Coupling in InAs Nanowires
Sebastian Heedt
We report on phase-coherent transport measurements on differently doped
InAs nanowires grown by selective area metalorganic vapor phase epitaxy.
The nanowires are contacted individually and the low-temperature electronic
transport properties are investigated for temperatures down to 30 mK and
magnetic fields up to 10 T. To this end, top-gates with high-k dielectrics are
prepared. At small current-bias the transport is phase-coherent and gives
us the opportunity to determine the phase-coherence length and the spin
relaxation length. The band profile and the carrier concentration of the
nanowires can be manipulated by the application of a gate voltage. An analytical
model for the low-field quantum conductivity correction is utilized
to quantify Rashba and Dresselhaus spin-orbit coupling effects. 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.
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