Are there stripes in the ET materials ?

Abstract

We propose that a central aspect of two-dimensional doped antiferromagnets, including the cuprate high temperature superconductors and the (BEDT-TTF) 2 X materials, is a dynamical dimension reduction in which the electrons self-organise in a quasi one-dimensional manner. Strong repulsive interactions between electrons frustrate their motion, resulting in a large zero-point kinetic energy. As a function of decreasing temperature, this kinetic energy is lowered in three steps that are reflected in a sequence of crossovers and phase transitions: first of all, the system develops a charge-inhomogeneous state -an array of one-dimensional metallic stripes that forms an electronic liquid crystal; this lowers the kinetic energy along a stripe. In the transverse direction in the planes, the kinetic energy is lowered by pair hopping, which first creates spin pairs and then, at a lower temperature, superconducting phase coherence. This constitutes a new mechanism and many-body theory of superconductivity. Evidence for this behaviour in the high temperature superconductors, and implications of the conjecture that similar behaviour occurs in the (BEDT-TTF) 2 X materials are described.