An investigation was made of  the charge transfer and the alterations of the electronic states due to local doping of a normal-state 45°-tilted [001] grain boundary in YBa2Cu3O7 by means of first-principles calculations. Considering Ca doping and O deficiency as prototypical modifications it was demonstrated that the redistribution of the charge carriers in the CuO2 planes displays a very complex spatial pattern, which deviates even qualitatively from the naive expectation

Effects of Ca Doping and O Deficiency on the Charge Distribution in the Vicinity of a 45° [001] Grain Boundary in YBa2Cu3O7. U.Schwingenschlögl, C.Schuster: EPL, 2012, 97[3], 37006