On the possible mechanism of superconductivity in cuprates and pnictides

The nature of the normal state and the mechanism of superconductivity in two families of high-temperature superconductors, cuprates and pnictides, remain a matter of intense discussions. According to band-structure calculations, confirmed by ARPES data, the electronic structure of pnictides differs considerably from that of cuprates. However, in spite of these differences, it looks like in both cases there exists some general and fairly "coarse" mechanism independent of fine details of the band structure and responsible for superconductive pairing in these materials. Here, we suggest a qualitative model describing the ground state and the mechanism of superconductive pairing in cuprates and pnictides that, in our opinion, can explain many of their unusual properties.