Theory of non-Fermi liquid and pairing in electron-doped cuprates

We apply the spin-fermion model to study the normal state and pairing instability in electron-doped cuprates near the antiferromagnetic quantum-critical point. Peculiar frequency dependencies of the normal state properties are shown to emerge from the self-consistent equations on the fermionic and bosonic self-energies, and are in agreement with experimentally observed ones. We argue that the pairing instability is in the d(x)(-y)(2)(2) channel, as in hole-doped cuprates, but theoretical T-c is much lower than in the hole-doped case. For the same hopping integrals and the interaction strength as in hole-doped materials, we obtain T-c similar to 10 K at the end point of the antiferromagnetic phase. We argue that a strong reduction of T-c in electron-doped cuprates compared to hole-doped ones is due to critical role of the Fermi surface curvature for electron-doped materials. The d(x)(-y)(2)(2)-pairing gap Delta(k,omega) is strongly nonmonotonic along the Fermi surface. The position of the gap maxima, however, does not coincide with the hot spots, as the nonmonotonic d(x)(-y)(2)(2) gap persists even at doping when the hot spots merge on the Brillouin zone diagonals.