Microscopic nature of erbium trapping sites in rare-gas solids

Characterize the microscopic nature, geometry, and formation of the trapping sites occupied by neutral erbium atoms in solid neon and solid argon, including how impurity–host interactions and host-lattice structure determine the trapping cavities.

Background

Thermal annealing produces different optical responses in solid neon and solid argon. In neon, annealing narrows the 1437-nm emission line and lengthens its lifetime, suggesting more uniform and less-quenched emitter environments, whereas argon retains broader lines and stretched, faster decays indicative of a wider distribution of local environments.

The measurements do not establish the microscopic structures responsible for these environments. In particular, the size and rigidity of an erbium trapping cavity cannot be inferred simply from the size of the host atoms, and prior studies indicate that neon may support multi-vacancy trapping sites whose geometry depends on both impurity–host interactions and the host lattice.