Single hole spin relaxation probed by fast single-shot latched charge sensing

Alex Bogan,Lisa Tracy,Marek Korkusinski,Louis Gaudreau,Piotr Zawadzki,John Reno,Terry Hargett,Sergei Studenikin,Andy Sachrajda

doi:10.1038/s42005-019-0113-0

Abstract

Hole spins have recently emerged as attractive candidates for solid-state qubits for quantum computing. Their state can be manipulated electrically by taking advantage of the strong spin-orbit interaction (SOI). Crucially, these systems promise longer spin coherence lifetimes owing to their weak interactions with nuclear spins as compared to electron spin qubits. Here we measure the spin relaxation time T1 of a single hole in a GaAs gated lateral double quantum dot device. We propose a protocol converting the spin state into long-lived charge configurations by the SOI-assisted spin-flip tunneling between dots. By interrogating the system with a charge detector we extract the magnetic-field dependence of T1 ∝ B−5 for fields larger than B = 0.5 T, suggesting the phonon-assisted Dresselhaus SOI as the relaxation channel. This coupling limits the measured values of T1 from ~400 ns at B = 1.5 T up to ~60 μs at B = 0.5 T.

Highlights

Hole spins have recently emerged as attractive candidates for solid-state qubits for quantum computing
Theory predicts a decrease of T1 with increasing magnetic field, with T1 ∝ B−5 for the Dresselhaus spinorbit interaction (SOI), or T1 ∝ B−9 for the Rashba SOI29,30
We report on the development of a technique to read out a single-hole spin qubit in one quantum dot by converting the spin state into a latched charge state in a secondary dot

Summary

Introduction

Hole spins have recently emerged as attractive candidates for solid-state qubits for quantum computing. By interrogating the system with a charge detector we extract the magnetic-field dependence of T1 ∝ B−5 for fields larger than B = 0.5 T, suggesting the phonon-assisted Dresselhaus SOI as the relaxation channel This coupling limits the measured values of T1 from ~400 ns at B = 1.5 T up to ~60 μs at B = 0.5 T. GaAs hole spins have a competitive edge, since their hyperfine interaction strength in bulk was predicted[9,10,11,12] and measured[13,14,15] to be an order of magnitude weaker than that of the electrons This suppression translates into improved values of T1, reaching 1 ms for holes in InGaAs samples[16,17]. With the exception of the Si device, all measurements mentioned above involved systems with several holes

Methods

Results

Conclusion