Intertwined chiral charge orders and topological stabilization of the light-induced state of a prototypical transition metal dichalcogenide

ROM 2019-08
Author: Dragan Mihailovic
Institute: Jozef Stefan Institute, Ljubljana
Publication: Gerasimenko et al., npj Quantum Materials 4, 32 (2019)
Instrument: LT NANOPROBE

The fundamental idea that the constituents of interacting many-body systems in complex quantum materials may self-organise into long-range order under highly non-equilibrium conditions leads to the notion that entirely new and unexpected functionalities might be artificially created. However, demonstrating new emergent order in highly non-equilibrium transitions has proven surprisingly difficult. In spite of huge recent advances in experimental ultrafast time-resolved techniques, methods that average over successive transition outcomes have so far proved incapable of elucidating the emerging spatial structure. Here, using scanning tunneling microscopy, we report for the first time the charge order emerging after a single transition outcome initiated by a single optical pulse in a prototypical two-dimensional dichalcogenide 1T-TaS2. By mapping the vector field of charge displacements of the emergent state, we find surprisingly intricate, long-range, topologically non-trivial charge order in which chiral domain tiling is intertwined with unpaired dislocations which play a crucial role in enhancing the emergent states' remarkable stability. The discovery of the principles that lead to metastability in charge-ordered systems opens the way to designing novel emergent functionalities, particularly ultrafast all-electronic non-volatile cryo-memories.

Authors: Yaroslav A. Gerasimenko1,2, Petr Karpov3,4, Igor Vaskivskyi1,2, Serguei Brazovskii4,5and Dragan Mihailovic1,2

1) CENN Nanocenter, Jamova 39, SI-1000 Ljubljana, Slovenia;
2) Department of Complex Matter, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia;
3) Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, Dresden 01187, Germany;
4) National University of Science and Technology "MISiS", Moscow, Russia and
5) CNRS UMR 8626 LPTMS, University of Paris-Sud, University of Paris-Saclay, Orsay, France

References: Stojchevska, L. et al. Ultrafast switching to a stable hidden quantum state in an electronic crystal. Science344, 177–180 (2014).