Fast nuclear spin hyperpolarization of phosphorus in silicon

TL;DR

This paper demonstrates a method to achieve high nuclear spin hyperpolarization in phosphorus-doped silicon, surpassing thermal equilibrium levels, with potential applications in quantum computing and MRI.

Contribution

It introduces a modified Overhauser process to hyperpolarize phosphorus nuclear spins to over 68% in silicon, a significant improvement over previous techniques.

Findings

Achieved over 68% nuclear polarization in phosphorus donors.

Polarization reached within approximately 150 seconds.

Operated at 1.37 K and 8.5 T magnetic field.

Abstract

We experimentally demonstrate a method for obtaining nuclear spin hyperpolarization, that is, polarization significantly in excess of that expected for a thermal equilibrium. By exploiting a modified Overhauser process, we obtain more than 68% nuclear anti-polarization of phosphorus donors in silicon. This polarization is reached with a time constant of ~150 seconds, at a temperature of 1.37 K and a magnetic field of 8.5 T. The ability to obtain such large polarizations is discussed with regards to its significance for quantum information processing and magnetic resonance imaging.