First principles investigation of local distortions in doped La2CuO4

We present the results of first-principles cluster calculations of local di stortions in doped La2CuO4. Local deformations of the CuO6 octahedra associ ated with the presence of an additional extrinsic hole were determined usin g the density-functional (DF) method on various cluster models. The results indicate that a localized hole induces a contraction of the CuO(apical) di stance from 2.40 to 2.28 Angstrom. The contracted distance is in Very good agreement with the anomalous, short CuO(apical) distance of 2.3 Angstrom, o bserved recently by polarized Cu K-edge extended x-ray absorption fine stru cture (EXAFS) in La1.85Sr0.15CuO4 and associated with the hole-rich stripe region.