[PAST EVENT] Physics Colloquium

November 16, 2018
4pm - 5pm
Small Hall, Room 111
300 Ukrop Way
Williamsburg, VA 23185Map this location
Fig. Current vs magnetic field (phase) data of a 5?m by 5?m SQUID. The result of the BdG calculation

Javad Shabani, Center for Quantum Phenomena, Physics Department, New York University, New York, 10003, Title of Talk: Superconducting proximity effect in two-dimensional semiconductor-superconductor structures

Abstract: Progress in the emergent field of topological superconductivity relies on synthesis of new material combining superconductivity, low density, and spin-orbit coupling. Theory indicates that the interface between a one-dimensional semiconductor with strong SOC and a superconductor hosts Majorana-modes with nontrivial topological properties. We present our recent developments in materials synthesis and growth of density-controlled surface 2D InAs quantum wells with epitaxial superconducting Aluminum. These developments have led to unprecedented control over proximity effect in semiconductors where electron densities can be tuned using a gate voltage. We demonstrate Josephson junctions with IV characteristic indicating highly transparent contacts. We focus on multiterminal junctions and superconducting quantum interference device (SQUID) geometry to investigate the subtle interplay between supercurrents and spin orbit interaction in these materials. The amplitude and shape of current phase plot is varied as critical currents in each arm are independently controlled using gate-tunable junctions. The data can be well described using solution of Bogoliubov–de Gennes equation for our SQUID junctions. We discuss potential applications in gate-based qubits as well as exploring topological superconductivity for computation.