Polaron effects on optical properties of semiconductor based spin-photon interfaces

Understanding the effects of vibrational modes on solid-state quantum bits proves a major challenge in developing robust spin-photon interfaces for semiconductor quantum computing architectures. Donor spins in silicon are known to exhibit remarkably long-coherence times making them attractive candidates for qubits, however the semiconductor environment introduces strong electron-phonon couplings which adversely effect the fidelity of the spin-photon interface, and therefore our ability to entangle qubits and perform quantum gate computations. In order to better understand the role of electron-phonon couplings in these systems, we study a microscopic model that captures the physical mechanisms inherent to these interactions in indirect bandgap semiconductors like silicon. In particular, we focus on the role played by non-local electron-phonon couplings which we find to have a substantial effect on the calculated lifetimes of the optical transitions pertaining to the donor atoms. We report on calculated fluorescence emission spectra that closely resemble phonon sideband formation and zero-phonon line characteristics in experimentally observed spectra, as well as identifing the physical mechanisms by which non-local electron-phonon couplings lead to zero-phonon line broadening.