Horst Rogalla

National Institute of Standards & Technology (NIST)

5 (Southwestern U.S.)

Email

Website

Horst Rogalla

5 (Southwestern U.S.)

Email

Website

Biography

Dr. Horst Rogalla was appointed as an IEEE CSC Distinguished Lecturer in 2013. Dr. Rogalla was born in Germany in 1947, studied physics and mathematics in Münster and did his habilitation in Giessen, both in Germany. After 2 years in the group of Prof. Tinkham in Harvard, he accepted in 1987 a professorship in Low-Temperature Physics at the University of Twente in the Netherlands from which he retired recently.

In his time at the University of Twente, he was Director of the Material Science Institute CMO for a number of years and a founding member of the MESA+ micro-/nano-technology institute. In the European Community, he was a member of the board of the Network of Excellence in Superconductivity SCENET and director of the European Network PiShift. He was a founding member of the European Society of Applied Superconductivity ESAS and the European Foundry Network FLUXONICS. He also organized major conferences in Superconductivity and Superconducting Electronics and many national and international workshops. Currently, he is a Research Professor at the University of Colorado and a scientist at NIST.

In his scientific career, he worked on the materials' properties of superconductors, their deposition as thin films and their application in Superconducting Electronics. Before the finding of High-Temperature Superconductivity (HTS), he worked on the application of Nb3Ge nano bridge Josephson-junctions in Superconducting Electronics operated in liquid hydrogen. After the finding of HTS, he invented the HTS ramp-type Josephson junction and developed with his co-workers in Twente an HTS integration technique, which resulted in superconducting circuits with up to 4 superconducting layers. This technique was successfully applied to HTS Superconducting Electronics devices. Later on, he was involved among others in the development of sd-wave Josephson junctions based on Nb/YBCO ramp-type junctions, which allowed to realize and apply π- Josephson junctions, in the development of integrated micro-coolers and the application of Nb-based Josephson junctions in highly sensitive magnetic sensors for biomagnetism and gravitation wave detectors.

Currently, he is working on noise thermometry using normal and superconducting electronics and also on arrays of YBCO split-ring resonators for cloaking applications.

He is a long-time member of the IEEE receiving the IEEE Max Swerdlow Award for Sustained Service to the Applied Superconductivity Community in 2011. In 2013, he was awarded an honorary lifetime voting membership on the board of the European Society of Applied Superconductivity (ESAS).

Affiliation(s)

National Institute of Standards & Technology (NIST)

2014

2018

Talk(s):

The Quest for Superconducting Supercomputers

Superconducting Electronics (SE) is around since quite a long time, covering in meantime the whole area from ultrasensitive sensors to extremely fast switching elements. In scientific applications, it has become quite a success story: Superconducting Quantum Interference Devices (SQUIDs) are used in applications that require very high sensitivity to magnetic flux or anything, magnetic flux can be derived from; Transition Edge Sensors (TES) begin to dominate the field of detector arrays in astronomical telescopes, and the digital operation of Single Flux Quantum (SFQ) circuits has been demonstrated up to a frequency of about 800 GHz. Nevertheless, the number and financial volume of commercial applications of SE is small and nearly not growing. But there could be a significant change coming: future supercomputers are so power-hungry that in a few generations each supercomputer would need an own electrical power station.

Superconducting digital circuits could be a way out of this dilemma. By using superconducting circuits the energy consumption can be reduced by 3 to 5 orders of magnitude (including the cooling) compared to equivalent semiconductor supercomputers. This has been recognized by one of the largest users of supercomputers in the USA, and recently a major project has been started to investigate ways how to realize such a computer. The main obstacle is posed by the need for a scalable and low-power superconducting memory. New ideas are needed since the classical SQUID-like memory cell is far too big for a large-scale integration. Magnetic Josephson junctions could be the way out, but they need to be scalable to nanometer dimensions, they need to be low-power and they need to be comparable in speed to semiconductor memories. In the area of interfacing to room-temperature electronics also new elements are needed, preferable three-terminal devices with power gain, being fast enough to overcome the need for parallelization.

The need of new superconducting memory elements and three-terminal devices requests the interaction with fundamental and device oriented research groups. Without having such devices available, the quest for a superconducting supercomputer will be a failure.

In this talk, I will shortly introduce Superconducting Electronics, give an overview over the supercomputer project and report on ongoing work for superconducting memory elements.