Momentum resolved tunneling in one-dimensional systems

This thesis presents measurements on one dimensional systems in GaAs cleaved
edge overgrowth (CEO) samples. Due to their unprecedented quality, the
quantum wires in these systems posses long mean free path of more than 10 μm
and large subband spacings exceeding 10 meV, which allow for the observation
of many effects characteristic to electronic transport in one dimension.
We investigate the finite size effects in tunneling between parallel quantum
wires with a density inhomogenuity induced by a top gate. This study dif-
fers from previous experiments in the inclusion of the gate voltage dependence
of conductance. By using both, experiments and numerical simulations, we
link the arising patterns in the tunnel conductance to the internal potential
landscape inside the quantum wire, enabling the characterization of various
sections of varying density. The finiteness of the wire implies that quantized
energy levels should exist. A combination of low temperature, good thermal-
ization and small DC-voltage bias and AC-excitations allows us to observe
Coulomb blockade in these long quantum wires, and extract the single particle
level spacing directly from the even/odd spacing of those Coulomb peaks.
We also investigate the dispersion of quantum Hall edge states and extract
their velocities using two independent methods, momentum resolved tunnel-
ing as a function of bias voltage (energy) and also as a function of gate voltage
(density), which agree well with each other. These measurements are per-
formed in the same CEO device and allow us to leverage our knowledge of the
quantum wire system, which is used as a spectrometer in these experiments.
We find excellent agreement between the extracted velocities and the predic-
tions for hard wall confined edge states.
The last two chapters cover phenomena of interacting electrons in one dimen-
sion. We observe further evidence for a spin selective Peierls transition by
measuring the increase of conductance on the non-universally quantized con-
ductance plateau as temperature is increased.
We also perform a systematic study of the zero bias anomaly in gate defined
quantum wire arrays, spanning a large temperature range of multiple decades,
and various densities, ranging from one to three subbands.