Supplementary information: quasi-particle tunneling across an
exciton condensate
Ding Zhang
1
;
2
, Joseph Falson
2
, Stefan Schmult
2
, Werner Dietsche
2
, and Jurgen H. Smet
2
1
State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics,
Tsinghua University, Beijing 100084, China
2
Max Planck Institute for Solid State Research,
Heisenbergstrasse 1, D-70569 Stuttgart, Germany
(Dated: May 6, 2020)
Abstract
In the supplementary information, we present simulation results of the potential profile and
density in the region of the quantum point contact (QPC). We also discuss the key transport
quantities derived from the Landauer-B ̈uttiker formalism and include additional data sets of the
tunnel conductance near
tot
= 1 for two different QPCs.
1
SIMULATION OF THE QUANTUM POINT CONTACT
Figure S1 shows the Hall bar structure together with the split gates that define the
quantum point contact (QPC). The split gates have a nominal separation of 4
m. They
are vertically displaced from the quantum wells by a spacer of approximately 710 nm. As
a result of this large separation, the orifice of the quantum point contact potential of the
two-dimensional electron gas (2DEG) is much narrower. To simulate this narrowing, 3D
self-consistent Poisson calculations were carried out with the nextnano software (nextnano
GmbH). Figure S2 displays the modeled structure and the calculated results. The real
wafer contains in-situ grown LT-GaAs and multiple superlattices on the substrate. This
complex heterostructure is simplified to the symmetric geometry shown in Fig. S2. To
minimize the computation time, the doping levels used were obtained by first running 1D
self-consistent Poisson-Schr ̈odinger tests until the density values in the two quantum wells
match experimental values in the balanced case [Fig. S2(a)]. In the following simulation, we
study the influence of top gates on this heterostructure. A gate voltage of