Development of a Scalable Quantum Memory Platform -- Materials Science of Erbium-Doped TiO$_2$ Thin Films on Silicon
Abstract
Rare-earth ions (REI) have emerged as an attractive candidate for solid-state qubits, particularly as a quantum memory. Their 4f-4f transitions are shielded by filled 5s and 5p orbitals, offering a degree of protection from external electric fields. Embedded within a thin film oxide host, REIs could enable a qubit platform with significant memory capabilities. Furthermore, a silicon-compatible thin film form factor would enable the use of standard semiconductor fabrication processes to achieve chip-based integrability and scalability for functional quantum networks. Towards this goal, we have carried out optical and microstructural studies of erbium-doped polycrystalline and epitaxial TiO thin films on Si (100), r-sapphire, and SrTiO (100). We observe that the inhomogeneous optical linewidth of the Er photoluminescence is comparable or better for polycrystalline Er:TiO(grown on Si) in comparison to single crystal epitaxial films on sapphire or SrTiO, implying a relative insensitivity to extended defects. We investigated the effect of the film/substrate and film/air interface and found that the inhomogeneous linewidth and spectral diffusion can be significantly improved via bottom buffer and top capping layers of undoped TiO. Using such approaches, we obtain inhomogeneous linewidths of 5.2 GHz and spectral diffusion of 180 MHz in Er:TiO /Si(100) films and have demonstrated the engineerability of quantum-relevant properties in these thin films.
Keywords
Cite
@article{arxiv.2202.05376,
title = {Development of a Scalable Quantum Memory Platform -- Materials Science of Erbium-Doped TiO$_2$ Thin Films on Silicon},
author = {Manish Kumar Singh and Gary Wolfowicz and Jianguo Wen and Sean E. Sullivan and Abhinav Prakash and Alan M. Dibos and David D. Awschalom and F. Joseph Heremans and Supratik Guha},
journal= {arXiv preprint arXiv:2202.05376},
year = {2022}
}
Comments
13 pages, 6 figures; corrects the units for spectral diffusion values (MHz throughout the manuscript instead of GHz(typo) in some places)