Superconductivity and Pseudogap in Quasi-Two-Dimensional Metals around the Antiferromagnetic Quantum Critical Point

Spin fluctuations (SF) and SF-mediated Superconductivity (SC) in quasi-two-dimensional metal around the anti ferrromagnetic (AF) quantum critical point (QCP) are investigated by using the self-consistent renormalization theory for SF and the strong coupling theory for SC. We introduce a parameter y(0) as a measure for the distance from the AFQCP which is approximately proportional to (x - x(c)), x being the electron (c) or hole (h) doping concentration to the half-filled band and x(c) being the: value at the AFQCP. We present phase diagrams in the T-y(0) plane including contour maps of the AF correlation length and AF and SC transition temperatures T-N and T-c, respectively. The T-c curve is dome-shaped with a maximum at around the AFQCP. The calculated one-electron spectral density shows a pseudogap in the high-density-of-states region near (pi, 0) below around a certain temperature T* and gives a contour map at the Fermi energy reminiscent of the Fermi arc. These results are discussed in comparison with e- and h-doped high-T-c cuprates.