Influence of spin structures and nesting on Fermi surface and a pseudogap anisotropy in tt.pdf

Influence of spin structures and nesting on Fermi surface and a pseudogap anisotropy in t-t’-U Hubbard model. 3 0 0 A.A.Ovchinnikov and M.Ya.Ovchinnikova. 2 y a Institute of Chemical Physics, RAS, Moscow, 119977, Kosygin str., 4. M 9 2 ] l e - r t Abstract s . t Influence of two types of spin structures on the form of the Fermi surface (FS) a m and a photoemission intensity map is studied for t − t′ − U Hubbard model. Mean - d field calculations are done for the stripe phase and for the spiral spin structure. It n o is shown, that unlike a case of electron doping, the hole-doped models are unstable c [ with respect to formation of such structures. The pseudogap anisotropies are dif- 1 ferent for h− and e− doping. In accordance with ARPES data for La Sr CuO 2−x x 4 v 5 the stripe phases are characterized by quasi-one-dimensional segments of FS in the 8 6 vicinity of points M (±π, 0) and by suppression of spectral weight in diagonal direc- 5 tion k = k . It is shown that spiral structures display the polarisation anisotropy: 0 x y 3 different segments of FS correspond to electrons with different spin polarisation. 0 / t a PACS: 71.10.Fd, 74.20.Rp, 74.20.-z m - The angular resolved photoemission spectroscopy (ARPES) is effective in the study of d n elect