Experimental determination of surface thermal expansion and electron–phonon coupling constant of 1T-PtTe2

Abstract

We report an extensive structural characterization of the surface of 1T-PtTe2 crystals by means of helium atom scattering (HAS) and ultra-high resolution scanning tunnelling microscopy (STM). HAS reveals that this bi-dimensional surface presents a large structural corrugation (∼) in direction. The surface lattice constant of PtTe2 derived from the positions of the helium diffraction peaks up to fifth order was found to be , in agreement with STM and x-ray diffraction measurements. This value remains unchanged in the temperature range between 90 and 580 K. These findings suggest that 1T-PtTe2 behaves similarly to graphene on a weakly-interacting substrate, for which the surface thermal expansion coefficient is zero within experimental error. The electron–phonon coupling constant has been determined by recording the thermal attenuation of the elastic diffraction peaks of PtTe2. Based on a recently developed quantum theoretical method adapted to layered degenerate semiconductors we find that lies between 0.38–0.42.