Enhancement of the d-wave pairing correlations by charge and spin ordering in the spin-one-half Falicov-Kimball model with Hund and Hubbard coupling

摘要

The projector quantumMonte Carlo method is used to examine the effects of the spin-independent U-fd as well as spin-dependent J(z) Coulomb interaction between the localized f and itinerant d electrons on the stability of various types of charge/spin ordering and superconducting correlations in the spin-one-half Falicov-Kimball model with Hund and Hubbard coupling. The model is studied for a wide range of f- and d-electron concentrations and it is found that the interband interactions U-fd and J(z) stabilize three basic types of charge/spin ordering, namely, i) the axial striped phases, ii) the regular n-molecular phases and iii) the phase-separated states. It is shown that the d-wave pairing correlations are enhanced within the axial striped and phase-separated states, but not in the regular phases. Moreover, it was found that the antiferromagnetic spin arrangement within the chains further enhances the d-wave paring correlations, while the ferromagnetic one has a fully opposite effect. Copyright (C) EPLA, 2016