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arXiv · 1204.0843

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

C. H. Yang·W. H. Lim·N. S. Lai·A. Rossi·A. Morello·A. S. Dzurak
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Abstract

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.

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C. H. Yang, W. H. Lim, N. S. Lai, A. Rossi, A. Morello, A. S. Dzurak. 2012-04-04. Orbital and valley state spectra of a few-electron silicon quantum dot. https://doi.org/10.1103/physrevb.86.115319

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