Related papers: Gate-defined Quantum Point Contact in an InSb Two-…
The temperature dependence of the conductance of a quantum point contact has been measured. The conductance as a function of the Fermi energy shows temperature-independent fixed points, located at roughly multiple integers of $e^{2}/h$.…
We analyze orbital effects of an in-plane magnetic field on the spin structure of states of a gated quantum dot based in a two-dimensional electron gas. Starting with a $k \cdot p$ Hamiltonian, we perturbatively calculate these effects for…
A clear signature of Zeeman split states crossing is observed in Landau fan diagram of strained germanium two-dimensional hole gas. The underlying mechanisms are discussed based on a perturbative model yielding a closed formula for the…
Recent theories suggest that the excitations of certain quantum Hall states may have exotic braiding statistics which could be used to build topological quantum gates. This has prompted an experimental push to study such states using…
The conductance quantization and shot noise below the first conductance plateau $G_0 = 2e^2/h$ are measured in a quantum point contact fabricated in a GaAs/AlGaAs tunnel-coupled double quantum well. From the conductance measurement, we…
Circularly-polarized magneto-photoluminescence (magneto-PL) technique has been applied to investigate Zeeman effect in InAs/InGaAs/InAlAs quantum wells (QWs) in Faraday geometry. Structures with different thickness of the QW barriers have…
The inverted band structure discovered in InAs/GaSb quantum well (QW) is found to host the topological quantum spin Hall (QSH) states. A QSH insulator hosts counterpropagating spin-polarized edge states that are protected by the…
Zeeman splitting of quantum-confined states of excitons in InGaAs quantum wells (QWs) is experimentally found to depend strongly on quantization energy. Moreover, it changes sign when the quantization energy increases with a decrease in the…
The appearance and evolution of an anomalous conductance plateau at 0.4 (in units of 2e2/h) in an In0.52Al0.48As/InAs quantum point contact (QPC), in the presence of lateral spin-orbit coupling, has been studied at T=4.2K as a function of…
High mobility InSb quantum wells with tunable carrier densities are investigated by transport experiments in magnetic fields tilted with respect to the sample normal. We employ the coincidence method and the temperature dependence of the…
We consider spin-resolved cyclotron trajectories in a magnetic focusing device with quantum point source and drain contacts defined within the InSb two-dimensional electron gas and their mapping by the scanning gate microscopy. Besides 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 report on the fabrication and electronic transport characterisation of Schottky-gated strongly confined Si/SiGe quantum point contacts (QPC). At zero magnetic field and T=450mK the QPC conductance as a function of gate voltage shows a…
A gate-defined quantum dot in an InAs nanowire is fabricated on top of a quantum point contact realized in a two-dimensional electron gas. The strong coupling between these two quantum devices is used to perform time-averaged as well as…
We report the observation of Kondo physics in a spin- 3/2 hole quantum dot. The dot is formed close to pinch-off in a hole quantum wire defined in an undoped AlGaAs/GaAs heterostructure. We clearly observe two distinctive hallmarks of…
We have calculated the admittance of a two-dimensional quantum point contact (QPC) using a novel variant of the Wigner distribution function (WDF) formalism. In the semiclassical approximation, a Boltzman-like equation is derived for the…
We have investigated the transport properties of one-dimensional (1D) constrictions defined by split-gates in high quality GaAs/AlGaAs heterostructures. In addition to the usual quantized conductance plateaus, the equilibrium conductance…
Recently, lithographic quantum dots in strained-Ge/SiGe have become a promising candidate for quantum computation, with a remarkably quick progression from demonstration of a quantum dot to qubit logic demonstrations. Here we present a…
g-factor tuning of electrons in quantum dots is studied as function of in-plane and perpendicular magnetic fields for different confinements. Rashba and Dresselhaus effects are considered, and comparison is made between wide- and narrow-gap…
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…