Electrical control of the g tensor of the first hole in a silicon MOS quantum dot
S. D. Liles (University of New South Wales)
F. Martins (Hitachi Cambridge Laboratory, University of New South Wales)
D. S. Miserev (University of Basel, University of New South Wales)
A. A. Kiselev (HRL Laboratories)
I. D. Thorvaldson (University of New South Wales)
M. J. Rendell (University of New South Wales)
I. K. Jin (University of New South Wales)
F. E. Hudson (University of New South Wales)
M. Veldhorst (TU Delft - TU Delft Services, Kavli institute of nanoscience Delft, University of New South Wales, TU Delft - QN/Veldhorst Lab, TU Delft - QuTech Advanced Research Centre)
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Abstract
Single holes confined in semiconductor quantum dots are a promising platform for spin-qubit technology, due to the electrical tunability of the g factor of holes. However, the underlying mechanisms that enable electric spin control remain unclear due to the complexity of hole-spin states. Here, we study the underlying hole-spin physics of the first hole in a silicon planar metal-oxide-semiconductor (MOS) quantum dot. We show that nonuniform electrode-induced strain produces nanometer-scale variations in the heavy-hole–light-hole (HH-LH) splitting. Importantly, we find that this nonuniform strain causes the HH-LH splitting to vary by up to 50% across the active region of the quantum dot. We show that local electric fields can be used to displace the hole relative to the nonuniform strain profile, allowing a mechanism for electric modulation of the hole g tensor. Using this mechanism, we demonstrate tuning of the hole g factor by up to 500%. In addition, we observe a potential sweet spot where dg(11¯0)/dV=0, offering a configuration to suppress spin decoherence caused by electrical noise. These results open a path towards a technology involving engineering of nonuniform strains to optimize spin-based devices.