Electronic structure of the α-(BEDT-TTF)2MHg(XCN)4 (M = Tl, K, NH4; X = S, Se) molecular metals: on the 1D vs. 2D character of the charge carriers

Abstract The relationship between the crystal structure and Fermi surface of the α-(BEDT-TTF) 2 MHg(XCN) 4 ( M = Tl , K , NH 4 ; X = S , Se ) molecular metals is discussed. A simple model to explain the origin of the different dimensionality of the carriers, i.e. one-dimensional (1D) holes but two-dimensional (2D) electrons, is presented.