In:
Science Advances, American Association for the Advancement of Science (AAAS), Vol. 6, No. 27 ( 2020-07-03)
Abstract:
The quantum coherence and gate fidelity of electron spin qubits in semiconductors are often limited by nuclear spin fluctuations. Enrichment of spin-zero isotopes in silicon markedly improves the dephasing time T 2 * , which, unexpectedly, can extend two orders of magnitude beyond theoretical expectations. Using a single-atom 31 P qubit in enriched 28 Si, we show that the abnormally long T 2 * is due to the freezing of the dynamics of the residual 29 Si nuclei, caused by the electron-nuclear hyperfine interaction. Inserting a waiting period when the electron is controllably removed unfreezes the nuclear dynamics and restores the ergodic T 2 * value. Our conclusions are supported by a nearly parameter-free modeling of the 29 Si nuclear spin dynamics, which reveals the degree of backaction provided by the electron spin. This study clarifies the limits of ergodic assumptions in nuclear bath dynamics and provides previously unidentified strategies for maximizing coherence and gate fidelity of spin qubits in semiconductors.
Type of Medium:
Online Resource
ISSN:
2375-2548
DOI:
10.1126/sciadv.aba3442
Language:
English
Publisher:
American Association for the Advancement of Science (AAAS)
Publication Date:
2020
detail.hit.zdb_id:
2810933-8
