Ryoichi Ishihara

Associate Professor, Group leader

Qutech, Dep. Quantum and Computer Engineering, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology

Ishihara-lab focuses on the integration technologies for unconventional electronic systems; quantum computers, quantum sensors, neuromorphic computers, and biodegradable sensors. Our work involves new materials, scalable fabrication of electronic and photonic devices, and 3D heterogeneous integration, aiming to realize unconventional electronic systems.

Automation of the characterization measurement of superconducting materials for quantum computer applications

Quantum computers must operate at extremely low temperatures in the order of a couple of milli Kelvin to preserve their quantum state. Therefore, it is crucial to minimize the heat dissipation at the vicinity of a quantum bit to prevent the loss of the quantum information. One method to do so is to select materials that dissipate low heat at the operating temperature of a quantum computer; superconductors are a perfect candidate owing to their unique property of conducting electricity with almost zero heat dissipation.

The two most important parameters of a superconductor are the critical temperature and the critical current density. The first parameter describes the temperature under which the material transitions from an ordinary conductor that dissipates heat to a superconductor that does not. The second parameter defines the maximum current density that can flow through a material without it losing its superconductor properties at a given temperature.

Figure 1. – Diagram of the boundary between the normal conductor and the superconductor states [1].