The spontaneous formation of double chemical terminated surfaces of La0.7Sr0.3MnO3 due to deviations from ideal epitaxial growth during its deposition on SrTiO3(001) is presented. The development of surface regions with differentiated topmost composition leads to outstanding surface nanostructuration presenting notably distinct local properties, particularly in terms of electric transport and local work function. Correlation between combined atomic force microscopy and X-ray photoelectron spectroscopy data allows the chemical identification of the two terminations as corresponding to La0.7Sr0.3O and MnO2. The most likely atomistic process at the origin of the surface organization has been interpreted by Monte Carlo simulations that reveal the importance of stacking fault formation as growth proceeds. We present a physical understanding of the experimental results for surfaces in which different electronic responses coexist. The conclusions of the present work can be extended to the growth of other perovskite thin films, therefore broadening the field of functional materials nanostructuration.

This work has been supported by the Spanish Government under projects MAT2013-47869-C4 and MAT2015-71664-R. The ICMAB members acknowledge the Spanish MINECO through the project MAT2015-68994-REDC and the Severo Ochoa Program (SEV-2015-0496), FEDER program and the Generalitat de Catalunya through 2014 SGR 501. L.L.M. thanks the Spanish MINECO for a FPI BES-2013-063424 fellowship. J.J.M. thanks the Centro de Computacioń Cientıfí ca (CCC) of the Universidad Autónoma de Madrid for computing time.

Peer reviewed