HTSC-glue in doped copper oxides and iron pnictides: mobile CT-excitons within in-plane Ginzburg HTSC-sandwich

Abstract

It is demonstrated that high critical temperature of superconducting transition in cuprates and new iron-based superconductors is reached because of the Little-Ginzburg exciton mechanism of HTSC when Cooper pairing of mobile charge carriers is mediated by excitons which characteristic energy is essentially higher than Debye one for phonons. The effectiveness of such mechanism in these doped compounds is provided due to a series of planar Ginzburg HTSC-'sandwiches': 'insulator'-'metal'- 'insulator' (stripe structure) naturally forming in conducting planes below the onset pseudogap temperature in the normal state. The parameters of mobile, planar charge-transfer (CT) excitons in outer 'insulating' plates of such in-plane HTSC-'sandwich' are exactly within the optimal range predicted by Ginzburg about forty years ago.