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RESEARCH PRODUCT

Ab initio calculations of the atomic and electronic structure of BaZrO3 (111) surfaces

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Abstract The paper presents and discusses the results of calculations of surface relaxations and energetics for the polar (111) surface of BaZrO 3 using a hybrid B3LYP description of exchange and correlation. On the (111) surface, both Zr- and BaO 3 -terminations were analyzed. For both Zr and BaO 3 -terminated BaZrO 3 (111) surface upper layer atoms, with the sole exception of BaO 3 -terminated surface Ba atoms, relax inwards. The Zr-terminated BaZrO 3 (111) surface second layer Ba atoms exhibit the strongest relaxation between all Zr and BaO 3 -terminated BaZrO 3 (111) surface atoms. The calculated surface relaxation energy for Zr-terminated BaZrO 3 (111) surface is almost fifteen times larger than the surface relaxation energy for BaO 3 -terminated BaZrO3 (111) surface. The surface energy for Zr-terminated BaZrO 3 (111) surface (7.94 eV/cell) is smaller, than the surface energy for BaO 3 -terminated (111) surface (9.33 eV/cell). The calculated BaZrO 3 optical bulk band gap, 4.79 eV is in an excellent agreement with the experimental value, 5.00 eV. The calculated optical band gap for the Zr- and BaO 3 -terminated BaZrO 3 (111) surfaces becomes smaller with respect to the bulk optical band gap.