Ultrafast all-optical manipulation of the charge-density wave in VTe2

Abstract

The charge-density-wave (CDW) phase in the layered transition-metal dichalcogenide VTe2 is strongly coupled to the band inversion involving vanadium and tellurium orbitals. In particular, this coupling leads to a selective disappearance of the Dirac-type states that characterize the normal phase, when the CDW phase sets in. Here, we investigate the broadband time-resolved reflectivity variations caused by collective and single-particle excitations in the CDW ground state of VTe2. With the aid of density functional perturbation theory simulations we unveil the presence of two collective amplitude modes of the CDW ground state. By applying a double-pulse excitation scheme, we show the possibility to manipulate these modes, gaining insights into the coupling between these two collective excitations and demonstrating a more efficient way to perturb the CDW phase in VTe2.