E. J. Mele — Page 6

arXiv1993

Luttinger Liquid Instability in the One Dimensional t-J Model

We study the t-J model in one dimension by numerically projecting the true ground state from a Luttinger liquid trial wave function. We find the model exhibits Luttinger liquid behavior for most of the phase diagram in which interaction strength and density are varied. However at small densities and high interaction strengths a new phase with a gap to spin excitations and enhanced superconducting correlations is found. We show this phase is a Luther-Emery liquid and study its correlation functions.

cond-mat↗

arXiv1992

Anisotropic Pairing on a Three-Band Fermi Surface for $A_3{\rm C}_{60}$

We study a model for anisotropic singlet pairing in $A_3{\rm C}_{60}$, using a realistic model for the Fermi surface in a hypothesized orientationally-ordered doped crystal. Anisotropic solutions are studied by combining numerical solutions to the gap equation in the low-temperature phase with a Landau expansion near the mean field critical temperature. We focus on a class of three-dimensional nodeless $d$-wave solutions to the model, which exhibit a fully developed gap everywhere on the Fermi surface, but non-BCS temperature dependence of the order parameter in the condensed state, a relatively large value of the low-temperature gap, $2Δ/kT_{\rm c}$ , and non-BCS structure in the quasiparticle spectrum near the gap.

cond-mat↗