Fermi Surface Renormalization in Two Spatial Dimensions

We discuss the renormalization induced by interactions of a two-dimensional truncated Fermi surface (FS) model.Using a field theoretical renormalization group method we calculate the critical renormalized physical chemical potential. We show that it either vanishes or approaches a non-zero value. We argue that the vanishing of the chemical potential is indicative of a further truncation of the FS we started with and might well represent an insulating spin liquid phase.Comment: Laboratorio de Supercondutividade Centro Intl.de Fis.da Materia Condensada-Un

Effective spin-fermion model for strongly correlated electrons

A modified spin-fermion model is proposed to describe the physics of the underdoped phase of the t-J model of strongly correlated electron

Limitations of the mean field slave-particle approximations

We show that the transformation properties of the mean field slave boson/fermion order parameters under an action of the global SU(2) group impose certain restrictions on their applications to describe the phase diagram of the t-J model.Comment: to appear in Phys. Rev.