Spin and orbital structure of the first six holes in a silicon metal-oxide-semiconductor quantum dot

S D Liles,M Veldhorst,R Li,A R Hamilton,A S Dzurak,F E Hudson,C H Yang

doi:10.1038/s41467-018-05700-9

Abstract

Valence band holes confined in silicon quantum dots are attracting significant attention for use as spin qubits. However, experimental studies of single-hole spins have been hindered by challenges in fabrication and stability of devices capable of confining a single hole. To fully utilize hole spins as qubits, it is crucial to have a detailed understanding of the spin and orbital states. Here we show a planar silicon metal-oxide-semiconductor-based quantum dot device and demonstrate operation down to the last hole. Magneto-spectroscopy studies show magic number shell filling consistent with the Fock–Darwin states of a circular two-dimensional quantum dot, with the spin filling sequence of the first six holes consistent with Hund’s rule. Next, we use pulse-bias spectroscopy to determine that the orbital spectrum is heavily influenced by the strong hole–hole interactions. These results provide a path towards scalable silicon hole-spin qubits.

Highlights

Valence band holes confined in silicon quantum dots are attracting significant attention for use as spin qubits
The spin states of electrons confined in semiconductor quantum dots form a promising platform for quantum computation[1,2,3]
Electron spins experience a strong hyperfine coupling to the nuclei spin of the host crystal, which limits spin coherence times[6]

Summary

Introduction

Valence band holes confined in silicon quantum dots are attracting significant attention for use as spin qubits. We present experimental observations of the first six hole states in a surface-gated silicon metal-oxide-semiconductor quantum dot.

Results

Conclusion