Journal Article

FZJ-2020-01659

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Large, Tunable Valley Splitting and Single-Spin Relaxation Mechanisms in a Si / Si x Ge 1 − x Quantum Dot

Hollmann, A. ; Struck, T. ; Langrock, V.FZJ* ; Schmidbauer, A. ; Schauer, F. ; Leonhardt, T. ; Sawano, K. ; Riemann, H. ; Abrosimov, N. V. ; Bougeard, D. ; Schreiber, L. (Corresponding author)FZJ*

2020
American Physical Society College Park, Md. [u.a.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/24620  doi:10.1103/PhysRevApplied.13.034068

Abstract: 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.

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Contributing Institute(s):

1. Theoretische Nanoelektronik (PGI-2)
2. JARA Institut Quanteninformation (PGI-11)

Research Program(s):

1. 144 - Controlling Collective States (POF3-144) (POF3-144)

Appears in the scientific report 2020

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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