Erbium implanted silicon for solid-state quantum technologies

TL;DR

This paper explores Erbium-implanted silicon as a quantum platform, demonstrating its coherence properties, defect states, and potential for optical spin polarization and high-temperature operation, with implications for quantum communication and computing.

Contribution

It reports the first detailed characterization of Erbium-implanted silicon's quantum properties, including coherence times, defect states, and coupling to resonators, highlighting its potential for quantum technologies.

Findings

Electron spin coherence time of ~10 μs at 5 K

Identification of a new Er-related defect state facilitating non-radiative relaxation

Collective coupling strength of ~1 MHz at 20 mK

Abstract

Erbium implanted silicon as a quantum technology platform has both telecommunications and integrated circuit (IC) processing compatibility. The electron spin coherence time of Er implanted Si with an Er concentration of 3X1017 cm-3 is measured to be ~10 {\mu}s at 5 K and the spin echo decay profile displays strong modulation due to super-hyperfine interaction with 29Si nuclei. Three independent measurements: temperature quenching of photoluminescence (PL), PL lifetime and photo-illuminated electron spin resonance (ESR) all indicate the presence of a previously unreported Er related defect state which can facilitate non-radiative relaxation from the Er exited state. This gives an energy level scheme analogous to that of the diamond NV centre, and implies that optical spin polarisation of the Zeeman ground state and high temperature operation of Er qubits in Er implanted Si may be feasible. The collective coupling strength between a superconducting NbN lumped-element microresonator and Er implanted Si with an Er concentration of 1017 cm-3 at 20 mK was ~ 1 MHz.