Nonequilibrium effects in vibrational modes pumped by inelastic tunneling
Phys. Rev. B 114, 105408 – Published 10 August, 2026
DOI: https://doi.org/10.1103/17p5-2cj9
Abstract
The properties of strongly correlated electron materials exhibit a surprising sensitivity to small lattice distortions, providing an opportunity for their tuning by selective distortion driving, usually achieved by optical excitations. Using inelastic electron tunneling in scanning tunneling microscopy, we demonstrate that, at the surface of a strongly correlated electron material, we can drive vibrational excitations out of equilibrium by studying the dynamics of localized modes on the Pd-terminated surface of the delafossite oxide . This surface forms a tiling of hydrogen clusters of varying sizes and shapes upon hydrogen adsorption. Our findings reveal that vibrational excitations in the clusters exhibit longer lifetimes than on typical metal surfaces. Detailed analysis of the spectroscopy data reveals signatures of nonequilibrium effects in the excitations which we attribute to the extended lifetimes of these modes. Theoretical calculations support that the long-lived nature of the excitations is related to the unique properties of the substrate.
