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arXiv · 1809.09799

Coherent order parameter dynamics in SmTe$_3$

M. Trigo·P. Giraldo-Gallo·M. E. Kozina·T. Henighan·M. P. Jiang·H. Liu·J. N. Clark·M. Chollet·J. M. Glownia·D. Zhu·T. Katayama·D. Leuenberger·P. S. Kirchmann·I. R. Fisher·Z. X. Shen·D. A. Reis
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Abstract

We present a combined ultrafast optical pump-probe and ultrafast x-ray diffraction measurement of the CDW dynamics in SmTe$_3$ at 300 K. The ultrafast x-ray diffraction measurements, taken at the Linac Coherent Light Source reveal a $\sim 1.55$ THz mode that becomes overdamped with increasing fluence. We identify this oscillation with the lattice component of the amplitude mode. Furthermore, these data allow for a more clear identification of the frequencies present in the optical pump-probe data. In both, reflectivity and diffraction, we observe a crossover of the response from linear (for small displacements) to quadratic in the amplitude of the order parameter displacement. Finally, a time-dependent Ginzburg-Landau model captures the essential features of the experimental observations.

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M. Trigo, P. Giraldo-Gallo, M. E. Kozina, T. Henighan, M. P. Jiang, H. Liu, J. N. Clark, M. Chollet, J. M. Glownia, D. Zhu, T. Katayama, D. Leuenberger, P. S. Kirchmann, I. R. Fisher, Z. X. Shen, D. A. Reis. 2018-09-26. Coherent order parameter dynamics in SmTe$_3$. https://doi.org/10.1103/physrevb.99.104111

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