Cooper Pair Splitting Using InAs Quantum Dots

When: Thursday, 10th April (2014), 12:00h
Place: Departamento de Física de la Materia Condensada, Facultad Ciencias, Module 3, Seminar Room (5th Floor).
Speaker: Dr. Szabolcs Csonka, Department of Physics, Budapest University of Technology and Economics and Condensed Matter Research Group of the Hungarian Academy of Sciences, Hungary.

An elegant idea for the creation of entangled electrons in a solid-state device is to split Cooper pairs, which are in a spin singlet state, by coupling a superconductor to two parallel quantum dots (QDs) in a Y-junction geometry. Such Cooper pair splitting (CPS) was successfully detected in InAs nanowires and carbon nanotubes based devices. After reviewing these earlier experiments we present the realization of a new generation of InAs Cooper pair splitter devices with gate control on the QDs parameters. We show that the CPS induced nonlocal signal strongly depends on the coupling of the QDs, it could even change its sign. Furthermore, it will be discussed how the singlet character of the spatially separated electrons can be detected by the spin qubit toolkit.