Toward high-throughput characterization of random spin baths in semiconductors*

Spin-defects in semiconductors, such as nitrogen-vacancy centers in diamond or divacancies in silicon carbide, are promising candidates for qubits, due to their optical addressability and relatively long coherence times. In most semiconductors, the hyperfine interaction of the central defect spin with isotopic nuclear spins is the main source of decoherence. Currently there are no automatic and efficient techniques for high-throughput characterization of local random nuclear spin baths in materials containing spin-defects, since direct experimental characterization is too time-consuming and labor-intensive for many samples. Although we can efficiently simulate dynamical decoupling experiments for a given configuration of nuclear spins, the inverse problem of recovering the hyperfine interactions from short dynamical decoupling experiments is ill-posed [1]. Using simulated data, however, we can augment short dynamical decoupling experiments to interpret the reliability and accuracy of hyperfine couplings extracted from these experiments. We developed a set of tools that can be used to validate the mathematical and physical bounds on proposed sets of hyperfine couplings obtained from data-driven, machine-learned, or advanced sampling methods. These tools can be used to guide experimental design for dynamical decoupling protocols and pave the way for high-throughput characterization of defects in semiconductors.

[1] M. Onizhuk & G. Galli. Adv. Theory. Simul. 2100254 (2021).