Publication

Revealing the role of electrons and phonons in the ultrafast recovery of charge density wave correlations in 1T-TiSe2

Helmuth Berger, Arnaud Magrez, Matthias Wolf
2016
Journal Articles

Abstract

Using time-and angle-resolved photoemission spectroscopy with selective near-and midinfrared photon excitations, we investigate the femtosecond dynamics of the charge density wave ( CDW) phase in 1T-TiSe2 as well as the dynamics of CDW fluctuations at 240 K. In the CDW phase, we observe the coherent oscillation of the CDW amplitude mode. At 240 K, we single out an ultrafast component in the recovery of the CDW correlations, which we explain as the manifestation of electron-hole correlations. Our momentum-resolved study of femtosecond electron dynamics supports a mechanism for the CDW phase resulting from the cooperation between the interband Coulomb interaction, the mechanism of excitonic insulator phase formation, and electron-phonon coupling.

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https://infoscience.epfl.ch/entities/publication/9a38e999-daf2-4cc7-b626-c62515efe1ac

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Helmuth Berger, Arnaud Magrez, Matthias Wolf
2016
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/9a38e999-daf2-4cc7-b626-c62515efe1ac

About this result

Related concepts (28)

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Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function. In the case of DFT, these are functionals of the spatially dependent electron density.

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