Aufsatz
Artikel (Publikationen im Open Access gefördert durch die UB)
Electronic origin of bond softening and hardening in femtosecond-laser-excited magnesium
Abstract
Many ultrafast structural phenomena in solids at high fluences are related to the hardening or softening of particular lattice vibrations at lower fluences. In this paper we relate femtosecond-laser-induced phonon frequency changes to changes in the electronic density of states, which need to be evaluated only in the electronic ground state, following phonon displacement patterns. We illustrate this relationship for a particular lattice vibration of magnesium, for which we—surprisingly—find that there is both softening and hardening as a function of the femtosecond-laser fluence. Using our theory, we explain these behaviours as arising from Van Hove singularities: We show that at low excitation densities Van Hove singularities near the Fermi level dominate the change of the phonon frequency while at higher excitations Van Hove singularities that are further away in energy also become important. We expect that our theory can as well shed light on the effects of laser excitation of other materials.
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Gefördert durch den Publikationsfonds der Universität KasselCollections
Publikationen (Theoretische Physik II - Theoretische Festkörper- und Ultrakurzzeitphysik)Artikel (Publikationen im Open Access gefördert durch die UB)
Citation
@article{urn:nbn:de:hebis:34-2014103146306,
author={Grigoryan, Naira S. and Zijlstra, Eeuwe S. and Garcia, Martin E.},
title={Electronic origin of bond softening and hardening in femtosecond-laser-excited magnesium},
journal={New Journal of Physics},
year={2014}
}
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<resource xsi:schemaLocation="http://datacite.org/schema/kernel-2.2 http://schema.datacite.org/meta/kernel-2.2/metadata.xsd"> 2014-10-31T12:26:19Z 2014-10-31T12:26:19Z 2014 1367-2630 urn:nbn:de:hebis:34-2014103146306 http://hdl.handle.net/123456789/2014103146306 Gefördert durch den Publikationsfonds der Universität Kassel eng IOP Urheberrechtlich geschützt https://rightsstatements.org/page/InC/1.0/ 530 Electronic origin of bond softening and hardening in femtosecond-laser-excited magnesium Aufsatz Many ultrafast structural phenomena in solids at high fluences are related to the hardening or softening of particular lattice vibrations at lower fluences. In this paper we relate femtosecond-laser-induced phonon frequency changes to changes in the electronic density of states, which need to be evaluated only in the electronic ground state, following phonon displacement patterns. We illustrate this relationship for a particular lattice vibration of magnesium, for which we—surprisingly—find that there is both softening and hardening as a function of the femtosecond-laser fluence. Using our theory, we explain these behaviours as arising from Van Hove singularities: We show that at low excitation densities Van Hove singularities near the Fermi level dominate the change of the phonon frequency while at higher excitations Van Hove singularities that are further away in energy also become important. We expect that our theory can as well shed light on the effects of laser excitation of other materials. open access In: New journal of physics. - London : IOP, 2014, 16, 013002, 1-11 Grigoryan, Naira S. Zijlstra, Eeuwe S. Garcia, Martin E. London doi:10.1088/1367-2630/16/1/013002 13002 New Journal of Physics S. 1-11 16 </resource>
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