Spectroscopic signatures of a bandwidth-controlled Mott transition at the surface of 1T-TaSe₂

A momentum-resolved high-resolution ARPES data which illustrate the spectral consequences of a bandwidth-controlled surface Mott transition in 1T-TaSe₂ is presented. The transition from a bad metal, characterized by a largely incoherent spectrum, to a correlated insulator is qualitatively captured by a DMFT calculation for the half-filled Hubbard model. Quantitative differences between theory and experiment show that the model should be extended to include the coupling to lattice degrees of freedom, in order to provide a more accurate description of electronic transitions in such charge-density waves (CDWs).