Interband excitation and carrier relaxation as displacive driving force for coherent phonons

E. M. Bothschafter, A. Paarmann, N. Karpowicz, E. S. Zijlstra, M. E. Garcia, F. Krausz, R. Kienberger, R. Ernstorfer

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

We report on displacive excitation of large amplitude coherent lattice motions in TiO2 under resonant conditions using sub-6-femtosecond UV pulses. Calculations of non-equilibrium potential energy surfaces reveal a new displacive mechanism for the coherent phonon generation, where a unidirectional displacement of the phonon potential occurs both instantaneously due to carrier excitation and dynamically due to cooling of the hot photo-excited carriers. The carrier cooling dynamics in TiO2 are faster than the phonon period, resulting in an initially anharmonic lattice motion. This effect manifests itself in an effective phase shift of the coherent phonon oscillation, in good agreement between our experiments and the calculations.

Original languageEnglish
Title of host publication18th International Conference on Ultrafast Phenomena, UP 2012
DOIs
StatePublished - 2013
Event18th International Conference on Ultrafast Phenomena, UP 2012 - Lausanne, Switzerland
Duration: 8 Jul 201213 Jul 2012

Publication series

NameEPJ Web of Conferences
Volume41
ISSN (Print)2101-6275
ISSN (Electronic)2100-014X

Conference

Conference18th International Conference on Ultrafast Phenomena, UP 2012
Country/TerritorySwitzerland
CityLausanne
Period8/07/1213/07/12

Fingerprint

Dive into the research topics of 'Interband excitation and carrier relaxation as displacive driving force for coherent phonons'. Together they form a unique fingerprint.

Cite this