Spin filling of valley-orbit states in a silicon quantum dot
  We report the demonstration of a low-disorder silicon metal-oxide-semiconductor (Si MOS) quantum dot containing a tunable number of electrons from zero to N=27. The observed evolution of addition energies with parallel magnetic field reveals the spin filling of electrons into valley-orbit states. We find a splitting of 0.10 meV between the ground and first excited states, consistent with theory and placing a lower bound on the valley splitting. Our results provide optimism for the realization in the near future of spin qubits based on silicon quantum dots. 
W. H. Lim, C. H. Yang, F. A. Zwanenburg, and A. S. Dzurak
cond-mat.mes-hall