Electrostatic potential shape of gate-defined quantum point contacts

Imaging in Quantum Point Contacts

Alessandro Cresti , Giuseppe Grosso (2) and Giuseppe Pastori Parravicini (3) (1) NEST-INFM, Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy, and Dipartimento di Fisica E. Fermi, Largo B. Pontecorvo 3, I-56127 Pisa, Italy [email protected] (2) NEST-INFM and Dipartimento di Fisica E. Fermi, Largo B. Pontecorvo 3, I-56127 Pisa, Italy (3) NEST-INFM and Dipartimento di Fisica ...

Gate-defined graphene quantum point contact in the quantum Hall regime.

We investigate transport in a gate-defined graphene quantum point contact in the quantum Hall regime. Edge states confined to the interface of p and n regions in the graphene sheet are controllably brought together from opposite sides of the sample and allowed to mix in this split-gate geometry. Among the expected quantum Hall features, an unexpected additional plateau at 0.5h/e2 is observed. W...

Scanning gate imaging of quantum point contacts and the origin of the 0.7 anomaly

Adiabatic dynamics of superconducting quantum point contacts.

Starting from the quasiclassical equations for non-equilibrium Green's functions we derive a simple kinetic equation that governs ac Josephson effect in a superconducting quantum point contact at small bias voltages. In contrast to existing approaches the kinetic equation is valid for voltages with arbitrary time dependence. We use this equation to calculate frequency-dependent linear conductan...

Conduction channels of superconducting quantum point contacts

Atomic quantum point contacts accommodate a small number of conduction channels. Their number N and transmission coe$cients M1 n N can be determined by analyzing the subgap structure due to multiple Andreev re#ections in the current}voltage (I}<) characteristics in the superconducting state. With the help of mechanically controllable break-junctions we have produced Al contacts consisting of a ...