Impact of Dopants on Electronic and Crystal Structure of Erbium-Doped Oxides for Quantum Memory

Quantum communication networks depend on qubits for secure long-distance data transmission. Rare-earth ion (REI) memory systems, particularly those utilizing erbium (Er³⁺) in oxide hosts with C-band emission, are crucial for synchronizing entanglement and amplifying signals within quantum networks [1,2]. Oxide materials offer several advantages, including ease of growth, compatibility with complementary metal-oxide-semiconductor (CMOS) technology, and long coherence times. However, embedding Er³⁺ ions introduce defects that disturb the host lattice, causing variations in photoluminescence linewidths and lifetimes in Er-doped oxide films—phenomena whose underlying mechanisms remain unclear [3,4]. In this study, we employed advanced synchrotron-based X-ray techniques at the Advanced Photon Source, including X-ray absorption spectroscopy and diffraction, to probe the electronic structure and lattice distortions in Er-doped titanium oxides across various doping levels [5]. This research is crucial for understanding and controlling the tunability of excited state lifetimes and linewidths, ultimately mitigating decoherence in quantum communication systems.