Structural dynamics of two-dimensional charge-density waves in CeTe 3 investigated by ultrafast electron crystallography

Tzong Ru T. Han, Zhensheng Tao, Subhendra D. Mahanti, Kiseok Chang, Chong Yu Ruan, Christos D. Malliakas, Mercouri G. Kanatzidis

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The electron-phonon mechanism that gives rise to various charge-ordered systems is often controversial because of the cooperative nature of the transformation, and because the structural aspect of the transformation is generally poorly understood. Using femtosecond electron crystallography, we reveal a two-step (-400 fs and 3.3 ps) suppression of the structural order parameter of a two-dimensional charge-density wave (CDW) that clearly decouples from its electronic counterpart following fs optical quenching. Through atomic fluctuational analysis on Bragg reflections and satellite features, we identify important momentum-dependent electron-phonon couplings appearing on both time scales that may be related to interactions between the unidirectional CDW collective modes, the lattice phonons, and the perturbed electronic subsystem. We show that the characteristic time scales of these couplings and relative fluctuational amplitudes as characterized by fs crystallography jointly determine the cooperativity between the electronic and structural subsystems, and from this it is possible to elucidate the underlying mechanism of the charge-ordered system.

Original languageEnglish
Article number075145
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number7
DOIs
Publication statusPublished - Aug 27 2012

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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