Orbital and valley state spectra of a few-electron silicon quantum dot

Understanding interactions between orbital and valley quantum states in silicon nanodevices is crucial in assessing the prospects of spin-based qubits. We study the energy spectra of a few-electron silicon metal-oxide-semiconductor quantum dot using dynamic charge sensing and pulsed-voltage spectros...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2012-09, Vol.86 (11), Article 115319
Main Authors: Yang, C. H., Lim, W. H., Lai, N. S., Rossi, A., Morello, A., Dzurak, A. S.
Format: Article
Language:English
Subjects:
Charge
Condensed matter
Orbitals
Qubits (quantum computing)
Qunatum dots
Silicon
Single-electron transistors
Spectra
Valleys
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Summary:Understanding interactions between orbital and valley quantum states in silicon nanodevices is crucial in assessing the prospects of spin-based qubits. We study the energy spectra of a few-electron silicon metal-oxide-semiconductor quantum dot using dynamic charge sensing and pulsed-voltage spectroscopy. The occupancy of the quantum dot is probed down to the single-electron level using a nearby single-electron transistor as a charge sensor. The energy of the first orbital excited state is found to decrease rapidly as the electron occupancy increases from N = 1 to 4. By monitoring the sequential spin filling of the dot we extract a valley splitting of ~ 230 mu eV, irrespective of electron number. This indicates that favorable conditions for qubit operation are in place in the few-electron regime.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.86.115319