Surface Phonon Dispersion of MoS2
AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
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The dispersion of phonons on the 0001 surface Of MoS2 was measured by high-resolution electron energy loss spectroscopy along both the 010 and 110 azimuths i.e., r to K and r to M, respectively. The surface phonons have lower energies than the corresponding bulk phonons, which indicates that the bonding interactions of the surface atoms are different from those of the bulk even in a layer lattice compound. Since sputtered MoS2 lubricant films are composed of many small crystallites, the relative number of surface atoms in a film is much higher than in a single crystal. The stronger bonding of the surface layer may affect the amount of inter- vs intracrystalline slip in the lubrication mechanism. This work also demonstrates the use and usefulness of a new technique high-resolution electron energy loss spectroscopy in this laboratory.
- Atomic and Molecular Physics and Spectroscopy