Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 51: Focus Session: Hybrid Quantum-Dot / Atom Systems
HL 51.7: Vortrag
Mittwoch, 22. März 2017, 12:15–12:30, POT 112
Relaxation of gate-controlled donor qubits in silicon — Peter Boross1, Gabor Szechenyi1, and •Andras Palyi2 — 1Eotvos University, Budapest, Hungary — 2Budapest University of Technology and Economics, Hungary
Gate control of donor electrons near interfaces is a generic ingredient of donor-based quantum computing. Here, we address the question: how is the phonon-assisted qubit relaxation time T1 affected as the electron is shuttled between the donor and the interface? We focus on the example of the ’flip-flop qubit’ (Tosi et al arXiv:1509.08538v1), defined as a combination of the nuclear and electronic states of a phosphorus donor in silicon, promising fast electrical control and long dephasing times when the electron is halfway between the donor and the interface. We theoretically estimate that the flip-flop qubit relaxation time can be of the order of 100 µs, 8 orders of magnitude shorter than the value for an on-donor electron in bulk silicon, and a few orders of magnitude shorter (longer) than the predicted inhomogeneous dephasing time (gate times). This relaxation process is boosted by (i) the nontrivial valley structure of the electron-phonon interaction, and (ii) the different valley compositions of the involved electronic states. Reference: P. Boross et al., Nanotechnology 27, 314002 (2016)