Bottom-up superconducting and Josephson junction devices inside a group-IV semiconductor.

Fabrication and measurement of a niobium persistent current qubit

Recent successes with superconducting Josephson junction qubits make them prime candidates for the implementation of quantum computing. This doctoral thesis details the study of a niobium Josephson junction circuit for quantum computing applications. The thesis covers two main areas: 1) the fabrication of sub-micron niobium Josephson junction devices using a Nb/Al/AlO./Nb trilayer process and 2...

Josephson Current in a Ferromagnetic Semiconductor/Semiconductor/Ferromagnetic Semiconductor Junction with Superconducting Contacts

Josephson Current For a Graphene Nanoribbon Using a Lattice Model

A tight binding approach based on the Bogoliubov-de Gennes approach has been used to calculate the DC Josephson current for a lattice model for S-GNR-S junctions , for short junctions with respect to superconducting coherence length. We calculate the phase, length, width and chemical potential dependence at the Josephson junction and discuss the similarities and differences with regard to the t...

Low-T, ramp-type Josephson junctions for SQUIDS

The Josephson tunnel junction is the basic element of a superconducting quantum interference device (SQUID). Amongst other parameters, the junction capacitance determines the characteristics of a (digital) SQUID. In a conventional dc SQUID, reducing the junction capacitance decreases the flux noise of the sensor, whereas in digital SQUIDs, the operating frequency can be increased when reducing ...

Theoretical proposal for superconducting spin qubits

We propose and theoretically investigate superconducting spin qubits. Superconducting spin qubit consists of a single spin confined in a Josephson junction. We show that owing to spin-orbit interaction, superconducting phase difference across the junction can polarize this spin. We demonstrate that this enables single-qubit operations and more complicated quantum gates, where spins of different...