Polar Oxides

Polar Oxides

  • Polar MgO(111)
  • Self-assembled gold atoms on FeO

Polar Oxides

  • Lattice structures with uncompensated charge distribution in the unit cell develop macroscopic dipole moment at the surface
  • Dipole compensation by reconstruction, metallization or adsorption of charged species onto the surface
  • Uncompensated surface polarity give rise to unusual physical and chemical phenomena (band bending, work-function changes, enhanced binding of adsorbates)

Polar MgO on Au(111)

  • MgO(111) develops polar structure with reduced distance between Mg2+-/O2- -planes with respect to the bulk
  • Formation of quasi metallic edge states at rims of the polar islands

For details: N. Nilius et al., Phys. Rev. B 86 (2012) 205410.

Self-assembly of Au atoms on polar FeO/Pt(111)

  • Variable registry at FeO-Pt interface alters Feδ+-/Oδ- bond length and thus local dipole moments in the film
  • Preferred Au binding to regions with high dipole strength triggers self-assembly into hexagonal atom pattern

For details: N. Nilius et al., Phys. Rev. Lett. 95 (2005) 066101.

(Changed: 2020-01-23)