Dynamic spin-lattice coupling and statistical interpretation for the molecularlike excitations in frustrated pyrochlores

Emergent molecularlike excitations have been discovered in a series of pyrochlore antiferromagnets, yet their origins and relationships with the coexisting magnon excitations remain a puzzle. Here, by incorporating dynamic spin-lattice coupling through the site-phonon model, we accomplish a unified description of the molecular and magnon excitations, which allows us to provide a statistical interpretation of the molecularlike modes.