TY  - JOUR
AU  - Hollmann, Arne
AU  - Struck, Tom
AU  - Langrock, Veit
AU  - Schmidbauer, Andreas
AU  - Schauer, Floyd
AU  - Leonhardt, Tim
AU  - Sawano, Kentarou
AU  - Riemann, Helge
AU  - Abrosimov, Nikolay V.
AU  - Bougeard, Dominique
AU  - Schreiber, Lars
TI  - Large, Tunable Valley Splitting and Single-Spin Relaxation Mechanisms in a Si / Si x Ge 1 − x Quantum Dot
JO  - Physical review applied
VL  - 13
IS  - 3
SN  - 2331-7019
CY  - College Park, Md. [u.a.]
PB  - American Physical Society
M1  - FZJ-2020-01659
SP  - 034068
PY  - 2020
AB  - Valley splitting is a key feature of silicon-based spin qubits. Quantum dots in Si/SixGe1−x heterostructures reportedly suffer from a relatively low valley splitting, limiting the operation temperature and the scalability of such qubit devices. Here, we demonstrate a robust and large valley splitting exceeding 200 μeV in a gate-defined single quantum dot, hosted in molecular-beam-epitaxy-grown 68Si/SixGe1−x. The valley splitting is monotonically and reproducibly tunable up to 15% by gate voltages, originating from a 6-nm lateral displacement of the quantum dot. We observe static spin relaxation times T1>1 s at low magnetic fields in our device containing an integrated nanomagnet. At higher magnetic fields, T1 is limited by the valley hotspot and by phonon noise coupling to intrinsic and artificial spin-orbit coupling, including phonon bottlenecking.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000522199100002
DO  - DOI:10.1103/PhysRevApplied.13.034068
UR  - https://juser.fz-juelich.de/record/874811
ER  -