Eur. Phys. J. B 22, 167-178 (2001)
https://doi.org/10.1007/PL00011140

Thermodynamics and optical conductivity of unconventional spin density waves

¹ Department of Physics, Technical University of Budapest, 1521 Budapest, Hungary
² Research Institute for Solid State Physics and Optics, PO Box 49, 1525 Budapest, Hungary

Corresponding author: ^a viro@szfki.hu

Received: 19 February 2001
Published online: 15 July 2001

Abstract

We consider the possibility of formation of an unconventional spin density wave (USDW) in quasi-one-dimensional electronic systems. In analogy with unconventional superconductivity, we develop a mean field theory of SDW allowing for the momentum dependent gap Δ(k) on the Fermi surface. Conditions for the appearance of such a low temperature phase are investigated. The excitation spectrum and basic thermodynamic properties of the model are found to be very similar to those of d-wave superconductors in spite of the different topology of their Fermi surfaces. Several correlation functions are calculated, and the frequency dependent conductivity is evaluated for various gap functions. The latter is found to reflect the maximum gap value, however with no sharp onset for absorbtion.