Continuous tuning of electronic correlations by alkali adsorption on layered 1T-TaS2

Kai Rossnagel

Institute for Experimental and Applied Physics, University of Kiel, Olshausenstr. 40, 24098 Kiel, Germany

Angle-resolved photoemission spectroscopy shows that a Mott- Hubbard type metal-insulator transition occurs at the Rb adsorbed surface of the layered charge-density-wave compound 1T-TaS2. The transition is driven by adsorption induced modifications of the charge-density wave and of the interlayer coupling, leading to an increase of the on-site Coulomb correlation energy and a narrowing of the Ta 5d band perpendicular to the layers, respectively. The continuous rearrangement of spectral weight is measured live during the deposition process. The experiments were carried out at the Electronic Structure Factory at beamline 7 of the Advanced Light Source in Berkeley. Work at the University of Kiel is supported by DFG Forschergruppe FOR 353. K.R. gratefully acknowledges support by the Alexander von Humboldt Foundation.