Giant Isotope Effect on the Excited-State Lifetime and Emission Efficiency of the Silicon T Centre

TL;DR

This study reveals a significant isotope effect on the excited-state lifetime and emission efficiency of the silicon T centre, with deuterium variants showing markedly improved quantum efficiency for quantum technology applications.

Contribution

We demonstrate a strong isotope dependence of the T centre's excited-state lifetime and explain it through first-principles calculations, highlighting potential for more efficient quantum emitters.

Findings

Deuterium T centre has over five times longer lifetime than protium.

Isotope substitution reduces vibrational mode energy, suppressing non-radiative decay.

Deuterium T centre approaches near-unity quantum efficiency.

Abstract

Efficient single-photon emitters are desirable for quantum technologies including quantum networks and photonic quantum computers. We investigate the T centre, a telecommunications-band emitter in silicon, and find a strong isotope dependence of its excited-state lifetime. In particular, the lifetime of the deuterium T centre is over five times longer than the common protium variant. Through explicit first-principles calculations, we demonstrate that this dramatic difference is due to a reduction in the carbon-hydrogen local vibrational mode energy, which suppresses non-radiative decay. Our results imply that the deuterium T centre approaches unit quantum efficiency, enabling more efficient single-photon sources, quantum memories, and entanglement generation.