Geometrical Effects on Valley-Orbital Filling Patterns in Silicon Quantum Dots for Robust Qubit Implementation

The effect of the geometrical confinement on the shell filling in quantum dots obtained in silicon-on-insulator (SOI) tri-sided gate metal oxide semiconductor single-electron transistors (MOSSETs) is investigated on the basis of the current spin density functional theory. Variations of the geometric shape in nanowire SOI-MOSSETs with square section entail important changes in the valley filling sequences, whereas the variability of the gate length does not imply a significant modification of the filling patterns. Our results provide quantitative insights towards the shell engineering of silicon quantum dots for qubits with stable valley filling patterns. (C) 2012 The Japan Society of Applied Physics