SPICE Workshop on Non-equilibrium Quantum Materials Design, June 27th - 29th 2023
Igor Vaskivskyi
The engineering of new orders in correlated materials has been a subject of intense research for decades. Notably, 1T-TaS2 has emerged as a prototypical system, parcularly following the discovery of long-lived hidden states that expanded its intricate equilibrium phase diagram. While there is strong evidence that these hidden orders are exclusively accessible through highly non-thermal excitaons, a comprehensive understanding of the underlying microscopic processes driving the phase transion and the unprecedented longevity of the reached states remains elusive.
In this study, we employ a combinaon of real- and reciprocal-space techniques to invesgate the dynamics of 1T-TaS2 aer photoexcitaon or carrier injecon, covering a broad temporal range spanning from femtoseconds to hours. Our integrated approach enables direct observaon of 3D structural changes, elucidang the interplay between in-plane charge density wave (CDW) reconfiguraon and out-of-plane restacking—a crucial parameter contribung to the system's insulang behavior in the thermal phase.
We aribute the stability of the hidden orders to the formaon of a network of topological defects induced by carrier injecon, which are revealed by scanning tunnelling microscopy. The transport properes of the system, on the other hand, cannot be explained within a purely 2D framework, necessitang the consideration of c-axis re-stacking. Remarkably, our results show that while both in- plane and out-of-plane reconfiguraons occur on sub-ps me scale, their dynamics exhibit disparies, which could have significant implicaons for real-world device applicaons.