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arXiv · 1209.0411

Ultrafast dynamics of charge density waves in 4Hb-TaSe2 probed by femtosecond electron diffraction

N. Erasmus·M. Eichberger·K. Haupt·I. Boshoff·G. Kassier·R. Birmurske·H. Berger·J. Demsar·H. Schwoerer
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Abstract

The dynamics of the photoinduced commensurate to incommensurate charge density wave (CDW) phase transition in 4Hb-TaSe2 are investigated by femtosecond electron diffraction. In the perturbative regime the CDW reforms on a 150 ps timescale, which is two orders of magnitude slower than in other transition-metal dichalcogenides. We attribute this to a weak coupling between the CDW carrying T-layers and thus demonstrate the importance of three-dimensionality for the existence of CDWs. With increasing optical excitation the phase transition is achieved showing a second order character in contrast to the first order behavior in thermal equilibrium.

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N. Erasmus, M. Eichberger, K. Haupt, I. Boshoff, G. Kassier, R. Birmurske, H. Berger, J. Demsar, H. Schwoerer. 2012-09-03. Ultrafast dynamics of charge density waves in 4Hb-TaSe2 probed by femtosecond electron diffraction. https://doi.org/10.1103/physrevlett.109.167402

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