Interaction of Light with Density Waves and Other Superlattices

In recent years, light has been used to manipulate the electronic properties of various charge density wave compounds. A metastable insulator-metal transition as well as mirror domain creation has been observed upon the application of a single light pulse in 1T-TaS2, while competing density waves can be observed away from thermal equilibrium in LaTe3. In this talk, I will present data demonstrating that chemical changes can also be instigated photo-thermally in the form of chemical intercalation in 1T-TaS2. Within a couple seconds of exposure to high intensity pulsed light, a polytypic structural transition can be induced along with chemical self-intercalation into the van der Waals gap. These intercalated atoms can order structurally and in other ways. Our work illustrates a new route towards photo-thermal manipulation of density wave compounds and paves the way for studies on similar quasi-two dimensional materials.