Coherence of single spins coupled to a nuclear spin bath of varying density

TL;DR

This study investigates how varying 13C nuclear spin concentration in diamond affects the coherence of single electron and nuclear spins, demonstrating control over multiple nuclei and analyzing decoherence mechanisms.

Contribution

It provides new insights into controlling multiple nuclear spins in diamond and quantifies how nuclear spin concentration impacts coherence times.

Findings

Coherent control of up to three nuclei in dense clusters.

Decoherence times decrease with increasing 13C concentration.

Long coherence times achieved in low-concentration diamond.

Abstract

The dynamics of single electron and nuclear spins in a diamond lattice with different 13C nuclear spin concentration is investigated. It is shown that coherent control of up to three individual nuclei in a dense nuclear spin cluster is feasible. The free induction decays of nuclear spin Bell states and single nuclear coherences among 13C nuclear spins are compared and analyzed. Reduction of a free induction decay time T2* and a coherence time T2 upon increase of nuclear spin concentration has been found. For diamond material with depleted concentration of nuclear spin, T2* as long as 30 microseconds and T2 of up to 1.8 ms for the electron spin has been observed. The 13C concentration dependence of T2* is explained by Fermi contact and dipolar interactions with nuclei in the lattice. It has been found that T2 decreases approximately as 1/n, where n is 13C concentration, as expected for an electron spin interacting with a nuclear spin bath.