Abstract
Nonequilibrium phase transitions play a pivotal role in broad physical contexts, from condensed matter to cosmology. Tracking the formation of nonequilibrium phases in condensed matter requires a resolution of the long-range cooperativity on ultra-short timescales. Here, we study the spontaneous transformation of a charge-density wave in CeTe3 from a stripe order into a bi-directional state inaccessible thermodynamically but is induced by intense laser pulses. With ≈100 fs resolution coherent electron diffraction, we capture the entire course of this transformation and show self-organization that defines a nonthermal critical point, unveiling the nonequilibrium energy landscape. We discuss the generation of instabilities by a swift interaction quench that changes the system symmetry preference, and the phase ordering dynamics orchestrated over a nonadiabatic timescale to allow new order parameter fluctuations to gain long-range correlations. Remarkably, the subsequent thermalization locks the remnants of the transient order into longer-lived topological defects for more than 2 ns.
Highlights
Nonequilibrium phase transitions play a pivotal role in broad physical contexts, from condensed matter to cosmology
The fluctuation effects associated with the symmetry breaking, which are beyond the mean-field description, are addressed by simultaneously following the scattering structure factors of the main and charge-density wave (CDW) super-lattice(s)
The structure factors are obtained in the region near the G401; we confirm the results obtained in other regions are similar
Summary
Nonequilibrium phase transitions play a pivotal role in broad physical contexts, from condensed matter to cosmology. The initial input parameters for LDWs, including QlðtÞ, u0;ηl ðtÞ, and ξlðtÞ, are deduced from fitting the experimental SQc and SQa. To deal with the dual order parameter system, with the fluctuations likely subject to the nonlinear effects from the softened modes, a second Voigt function is included to account for the different dynamics shown in the diffuse scattering of SQc (Fig. 3a).
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