New superconductivity induced by d-density wave in high-temperature superconductors

作者：Ha Kim; Subok Ri; Ilmyong Ri^*; Cheongsong Kim; Yuling Feng

来源：Physica B: Condensed Matter , 2010, 405(18): 3826-3830.

DOI：10.1016/j.physb.2010.06.010

• High-T(c) superconductor
• d-density wave
• Nonconventional mechanisms

We present a self-consistent theory of the interplay between the d-density wave (DDW) and superconductivity on the basis of the fluctuation-exchange (FLEX) approximation for the two-dimensional (20) Hubbard model with the nearest-neighbor hopping t and on-site Coulomb repulsion U. In order to stabilize the DDW state with respect to phase separation at lower dopings a small nearest-neighbor Coulomb repulsion V is included within the Hartree-Fock approximation. The competition between the DDW and superconductivity can generically result in the appearance of a new superconducting state, which has the pi-pairing order parameter. We solve the gap equations for competing DDW, BCS, and pi-pairing order parameters with d-wave symmetry, together with calculating the FLEX interaction self-consistently, and calculating the corresponding three transition temperatures T*, T(c), and T*(c) as a function of hole doping. The calculated phase diagram has a quantum critical point (QCP) separating a pure BCS superconducting state at large dopings delta > delta(0) from a coexisting DDW and pi-pairing state at lower dopings delta < delta(0). Remarka

• 出版日期2010-9-15
• 单位长春大学