Topological defects determine evolution of charge density wave phase transition

Quantum materials exhibit exotic properties and can exhibit new functionality and applications when brought out of equilibrium and changing their properties. These transient states are inherently inhomogeneous, characterized by the formation of topologically protected structures, requiring nanometer spatial resolution on femtosecond timescales to resolve their evolution. Total x-ray scattering of the charge density wave materials LaTe₃ were measured the Bernina beamline at SwissFEL. Using a sophisticated scaling analysis of diffuse scattering signals, unique and new insights into the dynamics on the relevant mesoscopic length scale show direct evidence of topological vortex strings of the charge density wave.  

These dislocations of the charge density wave after ultrafast excitation of LaTe3 leads to formation have been shown to modulate the equilibration process, which is slowed down by anomalous, subdiffusive dynamics.

These findings establish a novel general framework to investigate properties of topological defects, which occur in nonequilibrium phase transitions and can inhibit equilibration and thereby enhance competing ordering phenomena of very different properties .