Giant Kohn anomaly and the phase transition in charge density wave ZrTe3
Abstract
A strong Kohn anomaly in ZrTe3 is identified in the mostly transverse acoustic phonon branch along the modulation vector qP with polarization along the a* direction. This soft mode freezes to zero frequency at the transition temperature TP and the temperature dependence of the frequency is strongly affected by fluctuation effects. Diffuse x-ray scattering of the incommensurate superstructure shows a power law scaling of the intensity and the correlation length that is compatible with an order parameter of dimension n = 2.
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