Evidence for the formation of a Mott state in potassium-intercalated pentacene

Monica F. Craciun,1,2 Gianluca Giovannetti,3,4 Sven Rogge,1 Geert Brocks,4 Alberto F. Morpurgo,1,5 and Jeroen van den Brink3,6,7 1Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands 2Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan 3Institute Lorentz for Theoretical Physics, Leiden University, 2300 RA Leiden, The Netherlands 4Faculty of Science and Technology and MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands 5DPMC and GAP, University of Geneva, quai Ernest-Ansermet 24, CH-1211 Geneva 4, Switzerland 6Institute for Molecules and Materials, Radboud University, 6500 GL Nijmegen, The Netherlands 7Stanford Institute for Materials and Energy Sciences, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA Received 5 November 2008; revised manuscript received 9 January 2009; published 24 March 2009