Study of gossamer superconductivity and antiferromagnetism in the tJU model.pdf

Study of gossamer superconductivity and antiferromagnetism in the t-J-U model 1,2 1,3 1 4 Feng Yuan , Qingshan Yuan , C. S. Ting , and T. K. Lee 1 Texas Center for Superconductivity and Advanced Materials and Department of Physics, University of Houston, Houston, TX 77204 4 3 2 Department of Physics, Qingdao University, Qingdao 266071, China 0 Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, China 0 4 Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan 11529 2 (February 2, 2008) p The d-wave superconductivity (dSC) and antiferromagnetism are analytically studied in a renormal- e ized mean field theory for a two dimensional t-J model plus an on-site repulsive Hubbard interaction S U . The purpose of introducing the U term is to partially impose the no double occupancy constraint 2 by employing the Gutzwiller approximation. The phase diagrams as functions of doping δ and U 2 are studied. Using the standard value of t/J = 3.0 and in the large U limit, we show that the antiferromagnetic (AF) order emerges and coexists with the dSC in the underdoped region below ] n the doping δ ∼ 0.1. The dSC order parameter increases from zero as the doping increases and o reaches a maximum near the optimal doping δ ∼ 0.15. In the small U limi