Resumen de Optimal electronic doping in p-wave superconductors
B. Millán, L.A. Hernández Hernández, L.A. Pérez, J. Samuel Millán
Recently, within a generalized Hubbard model which includes correlated nearest (∆t) and next-nearest hopping interactions (∆t_(3)), a comparative study between d- and s^(∗)- wave superconducting ground states on a square lattice was performed. It was found that the critical temperature of transition T_(c)(n), as a function of the electron concentration n, reaches a maximum (T_(c−max)) at a given optimal doping (n_(op)) for each value of the ratio t′/t, where t and t′ are the tight-binding nearest and next-nearest hopping parameter of a square lattice, respectively. From all values obtained for T_(c−max)(t′/t, n_(op)) a global minimum one was encountered for both symmetries. Likewise, in the same space, a minimal ground state energy E_(g) was also obtained. Ford-wave channel both minima are localized around the same optimal doping. However, for s^(∗) symmetry, the two minima are located at different electron concentrations. In this work, we additionally study how the p-wave ground-state energy and the critical temperature depend on the hoppings parameters and the electron concentration. The results show that forp-wave, minimum global values of T_(c−max) and E_(g) in the (t′/t, n_(op)) space do exist too, and are found around half filling but, as occurs for s^(∗)- wave, the minimum of T_(c−max) does not occur at the same point as E_(g). Moreover, we present a ground-state phase diagramin the space (t′/t, n_(op)) where it is possible to find zones of coexistence and competition between the s^(∗)-, p- and d-wave symmetries. Also, an analysis of the shape of the Fermi surface and the single-particle energy, as functions of the wave vector of an electron in the Cooper pair, has been done for different regions of the mentioned space.
