Our research focuses on electrons and holes confined in semiconductor-based devices. For example, we study holes in germanium confined into two dimensions: The confinement of the valence band states is achieved by growing a heterostructure of SiGe barriers sandwiching the Ge quantum well. The emerging states possess a - compared to valence band states in other materials - unusually large mobility and small effective mass, which facilitates the confinement into high-quality low-dimensional devices by means of local topgate electrodes.
When confined into quantum dots, the discrete Zeeman-split states are used to encode the two states of a qubit. Within the NCCR SPIN project, we aim at understanding the characteristics of these discrete states so as to build fast qubits with low decoherence.
Super/Semi hybrid devices
When bringing Ge in close contact with a superconductor, the semiconductor becomes proximitized. Supercurrent can flow across the Ge junction, and this supercurrent is gate-tunable due to the possibility to gate the semiconductor. We are interested in the properties of the states emerging due to the interaction of the two types of material.
Bilayer graphene quantum dot qubits
Graphene is a 2D material with a linear dispersion relation. If two layes of graphene are coupled, a band gap opens, allowing to form quantum dots. In a collaboration with ETH Zürich, we are exploring bilayer graphene quantum dots as host for spin, valley or spin-valley qubits.
We have open PhD and postdoc positions for research on hole spins and quantum computing with germanium heterostructures!
Besides that, we are always looking for excellent and motivated people at all academic stages.
For applying, please send an email to A. Hofmann with your grades, your CV, your publications and/or a thesis, the contact details of one to three references and a short motivation stating your interest in working in our group.