Vibrational properties of transition metal dichalcogenides

This proposal aims at tracking the temperature dependence of the vibrational modes of technologically relevant semiconducting transition metal dichalcogenides (TMDs): MoSe2 and WS2. Inelastic xray scattering (IXS) is to be applied to measure the energy dispersion and width of the phonon modes of TMDs bulk crystals, as a function of temperature. The dispersion curves will be combined with vibrational density of states (vDOS), to identify the phonons modes involved in phonon-phonon, electron-phonon and exciton-phonon interactions, at the base of the temperature dependent, optical and transport properties of TMDs. Moreover, this study is to provide quantitative inputs for benchmarking atomistic models of mechanical (e.g. elastic tensor and moduli) and thermal (e.g. specific heat) properties of TMDs. These results will guide the device engineering and expand our understanding of phonon mediated processes in van der Waals crystals.