Light-induced reorganization of charge density wave stacking in 1T-TaS2

Abstract

Light is a powerful tool in sculpting the energy landscape of strong correlations. For example, low-intensity incoherent light is sufficient to change the way charge density wave (CDW) domains stack across layers of 1T-TaS2. The change in stacking type manifests in a large change in optical properties of 1T-TaS2 at room temperature. Much remains unknown about the mechanism of this light-induced stacking reorganization. Here, we study the temperature dependent optical tunability of 1T-TaS2 to probe the mechanism of the light-induced CDW stacking reorganization. We find that the optical tunability exhibits a peak at 250 K because of two opposing features. At lower temperatures, the domains grow bigger, and hence, the optical tunability is higher. However, the stacking reorganization becomes energetically less favorable at lower temperatures. The dynamics of tunability suggest that the mechanism of switching between the two stacking types could be explained by the classical nucleation theory. These findings shed light on the mechanism of the light-induced CDW stacking reorganization in 1T-TaS2 and such other layered CDW materials.