Stability and electronic structure of the $(1\times 1)$ SrTiO${}_3$(110) polar surfaces by first principles calculations

Abstract

The electronic and atomic structure of several $(1\times 1)$ terminations of the (110) polar orientation of SrTiO${}_3$ surface are systematically studied by first-principles calculations. The electronic structure of the two stoichiometric SrTiO- and O${}_2$-terminations are characterized by marked differences with respect to the bulk, as a consequence of the polarity compensation. In the former, the Fermi level is located at the bottom of the conduction band, while in the latter the formation of a peroxo bond between the two surface oxygens results in a small-gap insulating surface with states in the gap of the bulk projected band structure. We also consider three non stoichiometric terminations with TiO, Sr and O compositions, respectively, in the outermost atomic layer, which automatically allows the surface to be free from any macroscopic polarization. They are all insulating. The cleavage and surface energies of the five terminations are computed and compared, taking into account the influence of the chemical environment as a function of the relative richness in O and Sr. From our calculations it appears that some (110) faces can even compete with the TiO${}_2$ and SrO terminations of the (100) cleavage surface: in particular, the (110)-TiO termination is stable in Sr-poor conditions, the (110)-Sr one in simultaneously O- and Sr-rich environments. The available experimental data are compared to the outcomes of our calculations and discussed.

arXiv commentaccepted for publication in Phys. Rev. B

References in corpus (5)

• Ab initio pseudopotentials for electronic structure calculations of poly-atomic systems using density-functional theory
• The hematite (alpha-Fe_2 O_3) (0001) surface: evidence for domains of distinct chemistry
• The Effect of the Environment on alpha-Al_2O_3 (0001) Surface Structures
• Effect of quantum fluctuations on structural phase transitions in SrTiO_3 and BaTiO_3
• Ab-initio study of SrTiO3 surfaces

Cited by in corpus (10)

• Ab initio calculations of BaTiO3 and PbTiO3 (001) and (011) surface structure
• Ab initio calculations of the atomic and electronic structure of CaTiO3 (001) and (011) surfaces
• Electrostatic stability of insulating surfaces: Theory and applications
• Evolution of the Surface Structures on SrTiO${}_3$(110) Tuned by Ti or Sr Concentration
• First principle electronic, structural, elastic, and optical properties of strontium titanate
• Strain-induced Defect Superstructure on the SrTiO3(110) Surface
• Reversible Transition Between Thermodynamically Stable Phases with Low Density of Oxygen Vacancies on SrTiO${}_3$(110) Surface
• Surface enhanced covalency and Madelung potentials in Nb doped SrTiO${}_3$ (100), (110) and (111) single crystals
• Thickness Dependent Carrier Density at the Surface of SrTiO3 (111) Slabs
• Understanding oxide surface stability: Theoretical insights from silver chromate