Comparative investigation on RE(La,Ce)AlO3(100)/γ-Fe(100) interfaces: A first-principles calculation

Properties of gamma-Fe(100) surface, RE(La,Ce)AlO3(100) surfaces and RE(La,Ce)AlO3(100)/gamma-Fe(100) interfaces were investigated using a first-principles density functional plane-wave ultrasoft pseudopotential method. The results indicate that, the surface energy of gamma-Fe(100) surface is stabilized gradually with the increase of the slab thickness, and it converges to 2.16 j/m(2) ultimately. RE(La,Ce)AlO3(100) surface contains two terminated structures, which are REO-terminated one and AlO2-terminated one. When RE chemical potential (Delta mu(RE)) is smaller than -7.39 eV/unit cell (-2.84 eV/unit cell), AlO2-terminated surface is more stable than REO-terminated one. However, when Delta mu(RE) is larger than -7.39 eV/unit cell (-2.84 eV/unit cell), REO-terminated surface is more stable than AlO2-terminated one. For the RE(La,Ce)AlO3(100)/gamma-Fe(100) interfaces, the binding strength of AlO2-terminated structure is larger than that of the REO-terminated one. Moreover, for the same terminated structure, the binding strength of the LaAlO3(100)/gamma-Fe(100) interface is larger than that of the CeAlO3(100)/gamma-Fe(100) interface. When Delta mu(La) is in the range of -11.59 eV/unit cell similar to-11.22 eV/unit cell and -1.94 eV/unit cell similar to-1.56 eV/unit cell, LaAlO3 can be the heterogeneous nucleus of gamma-Fe; when Delta mu(Ce) is in the range of -6.27 eV/unit cell similar to-5.97 eV/unit cell, CeAlO3 can be the heterogeneous nucleus of gamma-Fe. (C) 2016 Elsevier B.V. All rights reserved.