Dresden 2020 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 21: 2D Materials II: Electronic Structure, Excitations, etc. (joint session O/CPP/HL)

HL 21.8: Talk

Monday, March 16, 2020, 17:00–17:15, WIL C107

Ab-initio structural dynamics of laser-excited graphene — •Sergej Krylow¹, Felipe Valencia Hernandez², Bernd Bauerhenne¹, and Martin E. Garcia¹ — ¹University of Kassel, 34132 Kassel, Germany — ²National University of Colombia, 111321 Bogota, Colombia

We calculate the response of graphene to an ultrafast laser pulse using ab initio density functional molecular dynamics simulations. Our results show a biexponential decay of the Bragg peak intenities of the (100) and (110) peaks. We are able to show that the fast decay is caused by the equilibration between the electrons and a few strongly coupled optical phonons (SCOPs). The slower decay can be attributed to the equilibration of the SCOPs to the other phonon modes. Furthermore, we analyze the decay pathways from the SCOPs to the other phonon modes.