Ultrafast optical absorption and coherent phonon generation in monolayer and bilayer transition metal dichalcogenides

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Abstract

When ultrashort laser pulses are applied to the solid-state material within a time scale less than the period of a particular phonon mode, the energy and momentum of the absorbed light are used by photo-excited carriers to interact collectively with the crystal lattices and generate lattice oscillations coherently, known as the coherent phonons. The Fourier transform of the absorption modulation due to the coherent phonon oscillations gives the coherent phonon intensity. In this work, we theoretically investigate the shape of coherent phonon intensity for transition metal dichalcogenides as a function of the polarization angle of the laser pulses. In particular, we focus on the E2g and A1g phonons in monolayer and bilayer molybdenum disulfides. Within the simplified theory of displacive excitation of coherent phonons, we find that the laser pulses uniquely select the electronic states in monolayer and bilayer molybdenum disulfides, resulting in a rich feature of the polar plots of the energy-dependent coherent phonon intensity of these materials.

Original languageEnglish
Article number012052
JournalJournal of Physics: Conference Series
Volume1816
Issue number1
DOIs
Publication statusPublished - 8 Mar 2021
Event10th International Conference on Theoretical and Applied Physics, ICTAP 2020 - Mataram, West Nusa Tenggara, Indonesia
Duration: 20 Nov 202022 Nov 2020

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