Results for High--T_c Cuprates Obtained from a Generalized Eliashberg Theory: Doping Dependence

Abstract

One of the most interesting problems in the field of high--$T_c$ superconductivity is the calculation of the generic phase diagram for both hole-- and electron--doped cuprates, as was discussed in the Introduction. Even after more than ten years of research, no general consensus on this question has been achieved. This problem is related to the microscopic origin of the mechanism of high--$T_c$ superconductivity because it would be highly desirable to explain the whole phase diagram for both hole-- and electron--doped superconductors within a unified theory. In particular, many non--Fermi--liquid properties in the normal state in the underdoped region have to be understood. In this section we shall show that our microscopic electronic theory, which assumes the exchange of antiferromagnetic spin fluctuations as the relevant pairing mechanism, can account for the main features in the phase diagram of both hole-- and electron--doped cuprate superconductors. ...