Charge-order gap in α-(BEDT-TTF)2I3

alpha-(BEDT-TTF)(2)I-3 is one of the best studied examples of a charge-ordered two-dimensional conductor The quarter-filled organic compound undergoes a sharp metal-to-insulator transition at T-CO = 135 K with a drastic Increase of the dc resistivity by many orders of magnitude The microwave and optical conductivity however reveals that the electrodynamics below T-CO is more complex Here we present optical investigations of below the charge-order transition that indicate a distinct temperature dependence (C) 2009 Elsevier B V All rights reserved