A singlet-triplet hole-spin qubit in MOS silicon

TL;DR

This paper demonstrates a high-quality singlet-triplet hole-spin qubit in planar silicon MOS quantum dots, showing rapid control, promising coherence times, and potential for scalable quantum computing architectures.

Contribution

It introduces a novel singlet-triplet hole-spin qubit in planar MOS silicon, with detailed analysis of control, coherence, and magnetic field effects, advancing silicon-based quantum computing.

Findings

Qubit control oscillations up to 400 MHz

Maximum dephasing time of 600 ns, extended to 1.3 μs with refocusing

Identification of magnetic field orientation for improved initialization

Abstract

Holes in silicon quantum dots are promising for spin qubit applications due to the strong intrinsic spin-orbit coupling. The spin-orbit coupling produces complex hole-spin dynamics, providing opportunities to further optimize spin qubits. Here, we demonstrate a singlet-triplet qubit using hole states in a planar metal-oxide-semiconductor double quantum dot. We observe rapid qubit control with singlet-triplet oscillations up to 400 MHz. The qubit exhibits promising coherence, with a maximum dephasing time of 600 ns, which is enhanced to 1.3 us using refocusing techniques. We investigate the magnetic field anisotropy of the eigenstates, and determine a magnetic field orientation to improve the qubit initialisation fidelity. These results present a step forward for spin qubit technology, by implementing a high quality singlet-triplet hole-spin qubit in planar architecture suitable for scaling up to 2D arrays of coupled qubits.