Regensburg 2016 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Gaede Prize Talks

O 36.2: Prize Talk

Tuesday, March 8, 2016, 14:00–14:30, H11

Ultrafast dynamics of many-body effects in solids and at interfaces: Polarons, excitons and correlated electrons — •Julia Stähler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

Optical excitation of solids can lead to various interesting non-equilibrium phenomena that occur on electronic time and energy scales. These, for instance, involve the interaction of excited charge carriers among each other as well as with the lattice degrees of freedom. Key ingredient for such many-body effects is the Coulomb interaction and, importantly, its screening. Modification of the latter on ultrafast timescales disturbs the balance of competing forces in a system and can, thus, give rise to interesting transient properties. Exemplary for the diversity of such many-body effects and their impact also on the equilibrium qualities of materials, I will discuss the following three phenomena:

(i) Ultrafast dynamics of charge injection, trapping and polaronic stabilization during the birth of a solvated electron [1]

(ii) Femtosecond electron relaxation and ultrafast formation of excitons at polar and non-polar ZnO surfaces [2]

(iii) Instantaneous insulator-to-metal transition in photoexcited monoclinic VO₂ [3]

[1] J. Stähler et al. J. Am. Chem. Soc. 137, 3520 (2015)

[2] J.-C. Deinert et al. Phys. Rev. Lett. 113, 057602 (2014)

[3] D. Wegkamp et al. Phys. Rev. Lett. 113, 216401 (2014)