SrTiO3(001)|LaAlO3(001) multilayers: A density-functional investigation


SrTiO3(001)|LaAlO3(001) multilayers: A density-functional investigation

Gemming, S.; Seifert, G.

SrTiO3(0 0 1)|LaAlO3(0 0 1) (STO|LAO) multilayers were investigated by density-functional band structure calculations. The lattice constant parallel to the interface equals roughly the average of the two constituents (3.81 Angstrom). The system contains two interface terminations: (I) SrO(0 0 1)|AlO2(0 0 1) with a spacing of 1.92 Angstrom as in STO and (II) TiO2(0 0 1)|LaO(0 0 1) with a spacing of 1.89 Angstrom as in LAO.
Additional displacements of the metal atoms close to the boundaries lead to rumplings of up to 0.06 Angstrom. A stoichiometric model is electronically neutral and insulating. Model systems with only termination I exhibit spatially localised holes in the O-based valence band; in systems with termination II the additional electron occupies the Ti-based conduction band. The strongly anisotropic dielectric constants obtained from linear response calculations show that the interface chemistry allows a fine tuning of perovskite multilayers.

Keywords: electronic structure; DFT; interfaces; non-linear dielectric properties; ferroic oxides

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Publ.-Id: 8694