engleski

SDW in cuprates - the role of oxygens

We investigate the SDW susceptibility around the pseudogap temperature T* in a realistic three- band model of the CuO_2 planes in high-Tc cuprates. This approach starts from initially empty copper orbitals and metallic oxygen holes which then hybridise with the copper sites. The magnetic scattering of two oxygen holes in the hybridised ground state introduces k-dependent spectral weights and projectors which can lead to a suppression of the logarithmic singularity (commensurate SDW response) even at the van Hove doping, in the presence of even slight disorder. We find the three-band structure, site-selective scattering, and small amount of disorder to be the minimal elements of complexity which cumulatively enable the incommensurate SDW response to survive up to optimal doping without involving superconductivity. The supression of the commensurate response already at one-loop level corresponds to the crossover from the weak-coupling to the strong-coupling regime, characteristic of complex materials.

Superconductivity; stripes; LDA; phase transitions

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