Characterization of the T center in $^{28}$Si

TL;DR

This study thoroughly characterizes the T center in silicon, revealing its optical and spin properties, and demonstrating its potential as a telecom-band quantum interface in silicon-based quantum technologies.

Contribution

First comprehensive analysis of T centers in $^{28}$Si, detailing their optical linewidths, excited state spectrum, and spin properties for quantum technology applications.

Findings

Zero phonon linewidths as narrow as 33 MHz

Observation of twelve orientational subsets of T centers

Identification of the T center as a promising quantum interface

Abstract

Silicon is host to two separate leading quantum technology platforms: integrated silicon photonics as well as long-lived spin qubits. There is an ongoing search for the ideal photon-spin interface able to hybridize these two approaches into a single silicon platform offering substantially expanded capabilities. A number of silicon defects are known to have spin-selective optical transitions, although very few of these are known to be in the highly desirable telecommunications bands, and those that do often do not couple strongly to light. Here we characterize the T center in silicon, a highly stable silicon defect which supports a short-lived bound exciton that upon recombination emits light in the telecommunications O-band. In this first study of T centers in $^{28}$Si, we present the temperature dependence of the zero phonon line, report ensemble zero phonon linewidths as narrow as 33(2) MHz, and elucidate the excited state spectrum of the bound exciton. Magneto-photoluminescence, in conjunction with magnetic resonance, is used to observe twelve distinct orientational subsets of the T center, which are independently addressable due to the anisotropic g factor of the bound exciton's hole spin. The T center is thus a promising contender for the hybridization of silicon's two leading quantum technology platforms.