QSE Quantum Seminar: "Graphene quantum devices", Klaus Ensslin

Please join us for the QSE Center Quantum Seminar with Klaus Ensslin from ETH Zurich who will give the talk "Graphene quantum devices" on Friday October 3 from 12pm to 1:30pm 
Location: GC A3 31

Pizzas will be available between the seminars at 12:00. All PhDs, postdocs, students, group leaders, and PIs are welcome to join us.

TITLE: "Graphene quantum devices"

ABSTRACT:
Graphene is a semimetal, but can become a semiconductor in case of bilayer graphene. High-quality quantum dots can be prepared in gate-defined bilayer graphene. Spin, charge and valley states have been identified and lifetimes have been measured. When bilayer graphene is van der Waals bonded with a neighboring layer of TMD (transition metal dichalcogenide) effects of spin-orbit interactions can be observed when the wavefunction in the bilayer graphene is close to the TMD. For quantum point contacts we demonstrate situations where the spin-orbit splitting is comparable to the orbital level splitting and can be tuned by gate voltages. Many of the techniques known for conventional quantum dots (Si, Ge, GaAs) can be applied to graphene quantum dots and give rise to unusual behavior of the level spectrum and its manipulation by gate electrodes. This makes bilayer graphene a contender for different kinds of qubits, such as charge, spin and valley, possibly in connection with superconducting regions in the same material.
This work was done in collaboration with Jonas Gerber, Efe Ersoy, Christoph Adam, Artem Denisov, Wister Huang, Michele Masseroni, Max Ruckriegel, Hadrien Duprez, Lisa Gächter, Chuyao Tong, Rebekka Garreis, and Thomas Ihn.

BIO:
Ensslin obtained his bachelor’s degree in physics from LMU Munich and his master’s degree from ETH Zurich (1981–1986), followed by doctoral studies at the Max-Planck-Institut for Solid State Research in Stuttgart (1986–1989). From 1989 to 1991, he held a postdoctoral appointment at the University of California, Santa Barbara, after which he was a University Assistant at LMU Munich (1991–1995). Since October 1995, he has been Professor of Physics at ETH Zurich. From 2011 to 2022, he served as Director of the National Center for Competence in Research on Quantum Science and Technology.