Meyerheim, H. L., Ernst, A., Mohseni, K., Maznichenko, I. V., Ostanin, S., Klimenta, F., Jedrecy, N., Feng, W., Mertig, I., Felici, R., Kirschner, J.
BaTiO3(001)-(2x1): Surface structure and spin density
Physical Review Letters 108, (21),pp 215502/1-5 (2012)
Using surface x-ray diffraction and ab initio calculations we present a model of the BaTiO3-(001)- (2x1) surface structure, which has not been considered so far. While the crystal is terminated by two TiO2 layers similarly to SrTiO−3(001)-(2x1), we find that one out of two surface layer Ti-atoms resides in a tetragonal pyramidal oxygen environment. This peculiar geometry leads to a metallic and magnetic surface involving local magnetic moments up to 2μB in magnitude located at surface Ti and O atoms. Our results are important for the understanding of the intrinsic surface metallicity of insulating oxides in general.
TH-2012-25