Antiferromagnetic insulating parent compounds

High temperature superconductivity in cuprates occurs upon hole doping in half-filled antiferromagnetic insulating parent compounds. More than 20 years has passed since the discovery of the high temperature superconductivity in cuprates [1], Despite very extensive and intensive researches, the mechanism for it is still not elucidated. 

The discovery of a high temperature cuprate superconductor by Bednorz and Miiller in 1986 [38] generated a renaissance in solid sate chemistry. The parent compound, La2Cu04, in fact, is an antiferromagnetic (AFM) insulator. Its structure is given in 16.47. Here, the small gray spheres are oxygen atoms, and the lar ge open spheres are... 

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