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arXiv · 0807.1022

Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe$_3$ (R = Ho, Dy, Tb)

R. V. Yusupov·T. Mertelj·J. -H. Chu·I. R. Fisher·D. Mihailovic
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Abstract

The coupling of phonons with collective modes and single-particle gap excitations associated with one (1d) and two-directional (2d) electronically-driven charge-density wave (CDW) ordering in metallic RTe_3 is investigated as a function of rare-earth ion chemical pressure (R=Tb, Dy, Ho) using femtosecond pump-probe spectroscopy. From the T-dependence of the CDW gap Δ_{CDW} and the amplitude mode (AM) we find that while the transition to a 1d-CDW ordered state at T_{c1} initially proceeds in an exemplary mean-field (MF) -like fashion, below T_{c1}, Δ_{CDW} is depressed and departs from the MF behavior. The effect is apparently triggered by resonant mode-mixing of the amplitude mode (AM) with a totally symmetric phonon at 1.75 THz. At low temperatures, when the state evolves into a 2d-CDW ordered state at T_{c2} in the DyTe_3 and HoTe_3, additional much weaker mode mixing is evident but no soft mode is observed.

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R. V. Yusupov, T. Mertelj, J. -H. Chu, I. R. Fisher, D. Mihailovic. 2008-07-07. Single-particle and collective mode couplings associated with 1- and 2-directional electronic ordering in metallic RTe$_3$ (R = Ho, Dy, Tb). https://doi.org/10.1103/physrevlett.101.246402

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