From Valence Bond Solid to Unconventional Superconductivity in the Organic Charge-transfer Solids

Mazumdar, S., Clay, R. T., & Li, H. (2009). From Valence Bond Solid to Unconventional Superconductivity in the Organic Charge-transfer Solids. Synthetic Metals. ICSM 2008, Pernambuco, Brazil.

Abstract

We show that superconductivity is absent within the 1/2-filled band triangular lattice repulsive Hubbard model that has been proposed for organic charge-transfer solids. We posit that organic superconductivity is rather reached from a bond-charge density wave that either constitutes the insulating state proximate to superconductivity, or is extremely close in energy to the antiferromagnetic state, and replaces the latter under pressure. The bond-charge density wave can be described within an effective attractive U extended Hubbard Hamiltonian with repulsive nearest neighbor interaction V. A first-order transition from the insulating to the superconducting state occurs within the model with increasing frustration.