Spin Selection Rule-Based Sub-Millisecond Hyperpolarization of Nuclear Spins in Silicon

TL;DR

This paper presents a rapid, magnetic field and temperature-independent method for hyperpolarizing nuclear spins in silicon, achieving high polarization within 100 microseconds, with potential applications in quantum information processing.

Contribution

The authors introduce a novel spin-dependent recombination scheme for fast nuclear spin hyperpolarization in silicon, demonstrating sub-millisecond polarization times and high polarization levels.

Findings

Achieved up to 66% nuclear spin polarization in silicon

Demonstrated polarization within less than 100 microseconds

Measured nuclear spin relaxation time of approximately 100 ms

Abstract

In this work, we devise a fast and effective nuclear spin hyperpolarization scheme, which is in principle magnetic field and temperature independent. We use this scheme to experimentally demonstrate polarizations of up to 66% for phosphorus donor nuclear spins in bulk silicon, which are created within less than 100 us in a magnetic field of 0.35 T at a temperature of 5 K. The polarization scheme is based on a spin-dependent recombination process via weakly-coupled spin pairs, for which the recombination time constant strongly depends on the relative orientation of the two spins. We further use this scheme to measure the nuclear spin relaxation time and find a value of approx. 100 ms under illumination, in good agreement with the value calculated for nuclear spin flips induced by repeated ionization and deionization processes.