Effect of interchain Coulomb interactions on the metal-insulator transition in quasi-one-dimensional systems: An experimental study based on homogeneous series of tetracyanoquinodimethane (TCNQ) salts

Abstract

Although the effect of interchain coupling on the metal-insulator transition in quasi-one-dimensional systems has been widely studied theoretically, experimental studies that prove this effect convincingly are rather scarce. A novel series of conducting ternary tetracyanoquinodimethane (TCNQ) salts, alkyl ammonium-TCNQ-iodide, was recently synthesized to examine experimentally the effect of interchain Coulomb interactions on the metal-insulator transition temperature ${T}_{c}$. The Coulom coupling between nearest-neighbor charge-density waves is calculated from the crystal structures, and a relationship between this coupling and ${T}_{c}$ is given. The role of the iodine counterion sublattice is discussed.