Nanoelectronics

There is an intense effort in information technology to find solutions to the problems emerging from the miniaturization of conventional complementary metal oxide semiconductor devices. In microelectronics, researchers are trying to create ever smaller and faster transistors by decreasing their dimensions or by choosing materials with different, more promising properties.

Researchers in basic research on the other hand are investigating new concepts which would allow information processing to operate on completely different principles. In this line, Loss and DiVincenzo suggested the use of electron spins confined in lithographically defined quantum dots (QDs) as elementary quantum bits (qubits) to realize a quantum computer (QC). So far, most of the experimental semiconductor work related to QC has focused on GaAs-based QDs. In GaAs QDs, however, the quantum coherence of electron spins is lost on relatively short time scales due to the hyperfine interaction with the nuclear spins.

In parallel to the development of spin qubits (SQs), there has recently been a huge wave of excitement in the prospect of using topological qubits (TQs) for QC. Such TQs are predicted to be robust versus decoherence. In the main focus of these proposals are the so-called Majorana fermions, introduced by Majorana more than 70 years ago. Various studies have suggested the use of topological insulators and semiconductor nanowires for the realization of Majorana fermions. Indeed, first experimental signatures of Majorana fermions have been reported in the past few years.

An intriguing perspective for quantum computation would open up if one were able to coherently transfer quantum information between SQs and TQs so as to combine the advantages of the two systems (SQs: easier manipulation and read out – TQs: more robust). In view of such a long-term dream, Ge-based nanostructures emerge as a very promising system, since they demonstrate an enormous potential both for SQs and Majorana bound states.

In our group, we study spin qubits in Ge-based systems, self-assembled QDs and lithographically defined QDs in two dimensional hole gases. In parallel we aim to understand whether Majorana fermions can be realized and detected in a hole-type system.

Contact

Georgios Katsaros
Institute of Science and Technology Austria (IST Austria)
Am Campus 1
A – 3400 Klosterneuburg

E-mail: georgios.katsaros@remove-this.ist.ac.at

CV and Publication List

Katsaros Group website

Assistant
Stephanie Danzinger

Phone: +43 (0)2243 9000-1124
E-mail:  stephanie.danzinger@remove-this.ist.ac.at

Team

  • Raimund Kirchschlager, Predoctoral Visiting Scientist
  • Josip Kukucka, PhD Student
  • Elisabeth Lausecker, Postdoc
  • Alisha Truhlar, PhD Student
  • Lada Vukusic, PhD Student
  • Hannes Watzinger, PhD Student

Selected Publications

  • Ares, N., Golovach, V. N., Katsaros, G., Stoffel, M., Fournel, F., Glazman, L. I., Schmidt, O.G. and De Franceschi, S. Nature of tunable g factors in quantum dots Phys. Rev. Lett. 110, 046602 (2013).
  • Zhang, J. J., Katsaros G., Montalenti, F., Scopece, D., Rezaev, R. O., Mickel, C., Rellinghaus, B., Miglio, L., De Franceschi, S., Rastelli, A. and Schmidt, O.G. Monolithic growth of ultra-thin Ge nanowires on Si(001) Phys. Rev. Lett. 109, 085502 (2012).
  • Katsaros, G., Golovach, V.N., Spathis, P., Ares, N., Fournel, F., Schmidt, O.G., Glazman, L.I. and De Franceschi S. Observation of spin selective tunnelling in SiGe nanocrystals Phys. Rev. Lett. 107, 246601 (2011).
  • Katsaros, G., Spathis, P., Stoffel, M., Fournel, F., Mongillo, M., Bouchiat, V., Lefloch, F., Rastelli, A., Schmidt O.G., and De Franceschi, S. Hybrid superconductor-semiconductor devices made from self-assembled SiGe nanocrystals on silicon Nature Nanotechnology 5, 458-464 (2010).
  • Katsaros, G., Tersoff, J., Stoffel, M., Rastelli, A., Acosta-Diaz, P., Kar, G. S., Costantini, G., Schmidt, O. G. and Kern, K. Positioning of strained islands by interaction with surface nanogrooves Phys. Rev. Lett. 101, 096103 (2008).

Career

As of 2016 Assistant Professor, IST Austria
Since 2012 Group Leader, Johannes Kepler University, Linz, Austria
2011–2012 Group Leader, Leibniz Institute for Solid State and Materials Research, Dresden, Germany
2006-2010 Postdoc at CEA, Grenoble, France
2006 PhD, Max Planck Institute for Solid State Research, Stuttgart, Germany
2001-2002 Research Assistant, National Center for Scientific Research “Demokritos”, Athens, Greece

Selected Distinctions

2013 ERC Starting Grant
2013 FWF START Award
2012 FWF Lise Meitner Fellowship
2011 Marie Curie Carrier Integration Grant

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