title: Electron-phonon interactions in MoS2 probed with ultrafast two-dimensional visible/far-infrared spectroscopy.
abstract: An ultrafast two-dimensional visible/far-IR spectroscopy based on the IR/THz air biased coherent detection method and scanning the excitation frequencies is developed. The method allows the responses in the far-IR region caused by various electronic excitations in molecular or material systems to be observed in real time. Using the technique, the relaxation dynamics of the photo-excited carriers and electron/phonon coupling in bulk MoS2 are investigated. It is found that the photo-generation of excited carriers occurs within two hundred fs and the relaxation of the carriers is tens of ps. The electron-phonon coupling between the excitations of electrons and the phonon mode E1u of MoS2 is also directly observed. The electron excitation shifts the frequency of the phonon mode 9 cm(-1) higher, resulting in an absorption peak at 391 cm(-1) and a bleaching peak at 382 cm(-1). The frequency shift diminishes with the relaxation of the carriers.
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005-1892, USA.
authors.forename: Xunmin
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005-1892, USA.
authors.forename: Hailong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005-1892, USA.
authors.forename: Xiewen
authors.initials: X
authors.lastname: Wen
authors.affiliation: Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005-1892, USA.
authors.forename: Junrong
authors.initials: J
authors.lastname: Zheng