Magnetic properties and electronic structure of S=1/2 spin gap compound BaCu(2)V(2)O(8)

Abstract

A detailed experimental as well as theoretical study is carried out to elucidate the origin of the spin gap in the quasi-one-dimensional compound BaCu(2)V(2)O(8). Our experimental analysis with the aid of careful magnetic susceptibility measurements on powder samples confirms that the magnetic behavior of this compound is best described by an isolated dimer model. We have also employed first principles calculations to study the electronic structure and magnetic properties of this low-dimensional spin gap compound. Using the self-consistent tight-binding linearized muffin-tin orbital (LMTO) method, and the Nth order LMTO method, we have identified the dominant exchange path by calculating the effective Cu-Cu hopping integrals. Our estimate of the alternation parameter alpha from the electronic structure calculations is consistent with that estimated from experiment confirming the validity of the isolated dimer model to explain the origin of the spin gap in this system.