Detection and Control of Dissipating Phonons

Abstract

We introduce the Tribo-Phonon Spectroscopy (TPS) developed to study phonons producing and dissipating at a tip-surface, which consists of an atomic force microscope (AFM) and a quartz-crystal microbalance (QCM). An AFM tip used to apply stresses generated lattice strain on an oscillating MoS₂(0001) surface, which dissipated via acoustic phonons. The dissipation energy of the phonons strongly depended on the size of the lattice strain. The motion of the acoustic phonons consisted of a longitudinal mode and a transverse mode, but the occurrence of their phonon modes depended on the crystallographic direction, which reflects the atomic arrangement of the MoS₂(0001) surface. In addition, we report that the acoustic phonons produced in MoS₂ islands are confined within MoS₂ islands smaller than the mean free path (MFP) of the phonons.