Dynamical control of electron spin coherence in a quantum dot: A theoretical study

TitleDynamical control of electron spin coherence in a quantum dot: A theoretical study
Publication TypeJournal Article
Year of Publication2007
AuthorsZhang WX, Dobrovitski VV, Santos LF, Viola L, Harmon BN
Journal TitlePhysical Review B
Volume75
Pages201302
Date PublishedMay
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000246890900005
KeywordsNUCLEI, systems
Abstract

We investigate the performance of dynamical decoupling methods at suppressing electron spin decoherence from a low-temperature nuclear spin reservoir in a quantum dot. The controlled dynamics is studied through exact numerical simulation, with emphasis on realistic pulse delays and the long-time limit. Our results show that optimal performance for this system is attained by a periodic protocol exploiting concatenated design, with control rates substantially slower than expected from the upper spectral cutoff of the bath. For a known initial electron spin state, coherence can saturate at long times, signaling the creation of a stable "spin-locked" decoherence-free subspace. Analytical insight into saturation is obtained for a simple echo protocol, in good agreement with numerical results.

DOI10.1103/PhysRevB.75.201302
Alternate JournalPhys. Rev. B