Speaker
Description
The interaction of complex solids with intense light pulses can induce novel emergent phenomena far from equilibrium. Prominent examples include optical enhancement of the critical temperature in certain superconductors and photo-stabilization of metastable states. A common theme in materials featuring exotic out-of-equilibrium behavior is the formation of charge density waves (CDWs), i.e., a coupled modulation of the charge density and crystal lattice. Here, using multidimensional photoemission spectroscopy, we investigate the electron dynamics of a prototypical CDW compound, TbTe3, after femtosecond optical excitation. Tracking the system’s order parameter during the photoinduced CDW melting and recovery reveals a surprising stability of CDW order at elevated electronic temperatures far greater than the thermal critical temperature, which we attribute to a transient suppression of lattice fluctuations. Furthermore, we demonstrate how the transient modification of the electronic band structure during the ultrafast CDW-to-metal transition impacts the elementary interactions, revealing the critical role of the phase space of electron-electron scattering. Our results provide an intuitive understanding of the electronic self-energy during an insulator-to-metal transition and are directly applicable to a broad range of materials.
