On high Tsub(c) superconductivity in La2CuO4 type compounds

We propose a new model for high-Tsub(c) superconductivity in the layer compounds of the La2CuO4 type. Starting from a doubly degenerate Hubbard model to describe the esub(g) hole of Cu2+, we show that the degeneracy is lifted due to an orbital superlattice which distorts the crystal and creates an antiferromagnetic interaction between the holes. As antiferromagnetism is not possible in this two dimensional model, we obtain a superconducting ground state due to the antiferromagnetic fluctuations. Order of magnitude is discussed for the superconducting temperature, the coherence length and the critical magnetic field Hc2. (author)