Long-lived state of a helium-like magnesium donor in silicon

TL;DR

This paper investigates the long-lived spin-triplet states of helium-like magnesium donors in silicon, revealing a 20 ms lifetime and relaxation governed by the Orbach mechanism with an activation energy near 13 meV.

Contribution

It demonstrates the existence of long-lived spin states in Mg donors in silicon and elucidates their relaxation mechanism and temperature dependence.

Findings

Long-lived spin-triplet states with ~20 ms lifetime.

Relaxation governed by the Orbach mechanism.

Activation energy close to 13 meV.

Abstract

The relaxation of ortho states of a helium-like Mg donor in silicon is investigated by measuring the modulation of background radiation transmission through impurity centers under pulsed photoexcitation. Long-lived states of the spin-triplet 1s(3T2) group with a lifetime of about 20 ms are observed. The temperature dependence indicates that the relaxation is governed by the Orbach mechanism with an activation energy ~13 meV, which is close to the exchange splitting energy of the excited 1s states of the Mg donor.