arxiv5/19/2026, 2:38:12 AM
Phonon Bottleneck Limits Spin Relaxation in Er³⁺:CaWO₄ at Millikelvin Temperatures — Implications for Rare-Earth Quantum MemoriesSpin-lattice relaxation in Er³⁺:CaWO₄ at millikelvin temperatures is governed by a phonon-bottleneck regime rather than intrinsic spin-phonon coupling, as evidenced by anomalously long and spin-excitation-dependent relaxation times. The relaxation behavior follows a distinctive […