Samsung Advanced Institute of Technology

Linear energy-momentum dispersion of Dirac electrons in graphene is altered by the Coulomb interaction as significant as energy bands in semiconductors and insulators. Its three-dimensional counterparts, Dirac and Weyl semimetals in layered materials, are also expected to host similar non-trivial interaction effects, modifying their bare energy bands. Especially, a precise knowledge of the interaction effects on a prototypical Weyl semimetal, MoTe2, is imperative to understand its intriguing topological and correlated states. Here, we report the direct evidence of impacts of the interaction in MoTe2 that alter its bare bands in a wide range of energy. Our quasiparticle interference measurements using scanning tunneling microscopy match simulation results with momentum-dependent self-energy corrections very well, while those with the other simpler approximations of the interaction fail to compute the correct number of quasiparticle pockets and shape of
their dispersions, respectively. With this, we predict a transition between type-I and type-II Weyl fermions with doping and resolve its different quantum oscillation experiments, thus highlighting the critical roles of Coulomb interactions in layered Weyl semimetals.