ar X iv : c on d - m at / 9 70 81 77 v 1 2 2 A ug 1 99 7 Theory of Photoemission from the Copper Oxide Material

ar X iv : c on d - m at / 9 50 81 21 v 1 2 6 A ug 1 99 5 On Quantum Solitons in the Sawtooth Lattice

We study the sawtooth lattice of a coupled spin 1/2 Heisenberg system, a variant of the railroad trestle lattice. The ground state of this system is twofold degenerate with periodic boundary conditions and supports kink antikink excitations, which are distinct in this case, unlike the railroad trestle lattice. The resulting low temperature thermodynamics is compared with the recently discovered...

ar X iv : c on d - m at / 9 40 70 67 v 1 1 3 Ju l 1 99 4 Phase Separation and Superconductivity in the Copper Oxide Chain

The phase diagram of the copper-oxide chain as a function of density and the nearest-neighbour Coulomb interaction, V , is determined. Phase separation takes place above a critical value of V when the Cu 2+ → Cu + valence fluctuations dominate. In the proximity of the phase separation boundary the superconducting correlations are the most divergent. We identify the parameter regions where the L...

ar X iv : c on d - m at / 9 70 80 30 v 1 [ co nd - m at . s up r - co n ] 5 A ug 1 99 7 1

ar X iv : h ep - l at / 9 70 80 09 v 1 1 5 A ug 1 99 7 SCREENING LENGTHS IN SU

We discuss the calculation of electric and magnetic screening masses in SU(2) gauge theory. The temperature dependence of these masses obtained from the long-distance behaviour of spatial correlation functions has been analyzed for temperatures up to 10 4 Tc.

ar X iv : c on d - m at / 9 70 30 28 v 1 3 M ar 1 99 7 In - plane optical response of Bi 2 Sr 2 CuO 6

We report on infrared reflectivity measurements of the ab-plane response of superconducting Bi2Sr2CuO6 single crystals. The frequency dependent conductivity has a maximum near 500 cm at room temperature, which shifts to lower frequency and merges with a Drude peak below 100 K. We attribute the unusual behavior of the mid-infrared conductivity to low frequency transitions between electronic band...