Related papers: Quantized conductance in an AlAs 2D electron syste…
We present a versatile design of freely suspended quantum point contacts with particular large one-dimensional subband quantization energies of up to 10meV. The nanoscale bridges embedding a two-dimensional electron system are fabricated…
One-dimensional quantized conductance is derived from the electrons in a homogeneous electric field by calculating the traveling time of the accelerated motion and the number of electrons in the one-dimensional region. As a result, the…
Quantum point contacts (QPC) are fundamental building blocks of nanoelectronic circuits. For their emission dynamics as well as for interaction effects such as the 0.7-anomaly the details of the electrostatic potential are important, but…
We investigate integer and fractional quantum Hall states in quantum point contacts (QPCs) of different geometries, defined in AlGaAs/GaAs heterostructures employing different doping and screening techniques. We find that, even in the…
Understanding topological matter in the fractional quantum Hall (FQH) effect requires identifying the nature of edge state quasiparticles. FQH edge state at the filling factor $\nu=2/3$ in the spin-polarized and non-polarized phases is…
In this work we analyze how coherent transport through a Quantum Dot (QD) in the Kondo regime is affected by the weak capacitive interaction with a nearby biased Quantum Point Contact (QPC). We find that when the QD-QPC interaction is weak…
A quantum point contact (QPC) is a very basic nano-electronic device: a short and narrow transport channel between two electron reservoirs. In clean channels electron transport is ballistic and the conductance $G$ is then quantised as a…
We investigate the transmission of electrons through a quantum point contact by using a quasi-one-dimensional model with a local bound state below the band bottom. While the complete transmission in lower channels gives rise to plateaus of…
Two-terminal conductance quantization in the context of quantum Hall (QH) physics is intimately related to the current carried by a discrete number of chiral edge modes. Upon pinching off a QH bar, one may engineer setups where some modes…
Quantum spin transport is studied in an interacting quantum dot. It is found that a conductance "plateau" emerges in the non-linear charge conductance by a spin bias in the Kondo regime. The conductance plateau, as a complementary to the…
We designed and performed low temperature DC transport characterization studies on two-dimensional electron gases confined in lattice-matched In$_{0.53}$Ga$_{0.47}$As/In$_{0.52}$Al$_{0.48}$As quantum wells grown by molecular beam epitaxy on…
We investigate a dephasing mechanism in a quantum dot capacitively coupled to a quantum point contact. We use a model which was proposed to explain the 0.7 structure in point contacts, based on the presence of a quasi-bound state in a point…
We investigate an electrostatically defined quantum point contact in a high-mobility InSb two-dimensional electron gas. Well-defined conductance plateaus are observed, and the subband structure of the quantum point contact is extracted from…
We demonstrate that, in a quasi-two-dimensional electron system confined to an AlAs quantum well and occupying two conduction-band minima (valleys), a parallel magnetic field can couple to the electrons' orbital motion and tune the energies…
Ge/SiGe quantum well heterostructures confining a high-mobility two-dimensional hole gas (2DHG) have emerged as a compelling platform for hybrid superconductor(S)-semiconductor(Sm) quantum devices. Here, we investigate the low-temperature…
Quantum point contacts are fundamental building blocks for mesoscopic transport experiments and play an important role in recent interference- and fractional quantum Hall experiments. However, it is not clear how electron-electron…
The semiconductor quantum point contact has long been a focal point for studies of one-dimensional electron transport. Their electrical properties are typically studied using ac conductance methods, but recent work has shown that the dc…
We study the ballistic magnetotransport in a double quantum point contact (QPC) device consisting of a quasi-one-dimensional quantum wire with an embedded island-like impurity - etched nano-hole as in a recently published experiment [J. C.…
Propagation of an electron wave packet through a quantum point contact (QPC) defined by electrostatic gates in bilayer graphene is investigated. The gates provide a bias between the layers, in order to produce an energy gap. If the gates on…
Quantum point contacts (QPC) are a key instrument in investigating the physics of edge excitations in the quantum Hall effect. However, at not-so-high bias voltage values, the predictions of the conventional point QPC model often deviate…