Toward precise simulations of the coupled ultrafast dynamics of electrons and atomic vibrations in materials

Ultrafast spectroscopies can access the dynamics of electrons and nuclei at short timescales, shedding light on nonequilibrium phenomena in materials. However, development accurate calculations to interpret these experiments has lagged behind as widely adopted simulation schemes are limited subpicosecond timescales or employ simplified interactions lacking quantitative accuracy. Here we show a precise approach obtain time-dependent populations atomic vibrations (phonons) up tens picoseconds, with femtosecond time resolution. Combining first-principles electron-phonon phonon-phonon parallel numerical scheme time-step coupled electron phonon Boltzmann equations, our method provides microscopic insight into scattering mechanisms excited Focusing graphene case study, demonstrate ultrafast dynamics, transient optical absorption, structural snapshots, diffuse x-ray scattering. Our paves way for atomistic simulations materials.Received 13 October 2020Accepted 6 April 2021DOI:https://doi.org/10.1103/PhysRevResearch.3.023072Published by American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution this work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasElectron-phonon couplingPhononsUltrafast phenomenaPhysical SystemsGrapheneTechniquesBoltzmann theoryDensity functional theoryFirst-principles calculationsCondensed Matter & Materials Physics