Zero field splitting of heavy-hole states in quantum dots

TL;DR

This paper reports the observation of a zero field splitting in heavy-hole states within quantum dots, caused by spin-orbit coupling and confinement, impacting hole spin qubit operation.

Contribution

It provides experimental evidence of zero field splitting in heavy-hole states due to spin-orbit effects in quantum dots, a novel insight for quantum computing applications.

Findings

Observed 55 μeV zero field splitting in heavy-hole triplet states

Spin degeneracy is lifted by spin-orbit coupling and confinement

Effect is relevant for broad class of hole quantum-dot systems

Abstract

Using inelastic cotunneling spectroscopy, we observe a 55{\mu}eV zero field splitting in the spin triplet manifold of Ge hut wire quantum dots. The degeneracy of the heavy hole triplet state is lifted since the interplay of strong spin orbit coupling and strong confinement leads to a preferred direction of the heavy-hole pseudospin. The reported effect should be observable in a broad class of strongly confined hole quantum-dot systems and needs to be considered when operating hole spin qubits.