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Ab initio calculations of ferroelectric instability in PbTiO3 capacitors with symmetric and asymmetric electrode layers

: Umeno, Y.; Albina, J.M.; Meyer, B.; Elsässer, C.

Fulltext urn:nbn:de:0011-n-1332080 (368 KByte PDF)
MD5 Fingerprint: e1d479b73b0cb7e4291c1a05c3904b38
Created on: 30.3.2012

Physical Review. B 80 (2009), No.20, Art.205122, 8 pp.
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
Journal Article, Electronic Publication
Fraunhofer IWM ()
ferroelectric material; PbTiO3; ab-initio calculation; thin-film capacitor

To investigate the influence of sym. and asym. electrode layers on ferroelec. properties of perovskite capacitors, ab initio calcns. based on d.-functional theory using the local d. approxn. and the mixed-basis pseudopotential method are performed for Pt/PbTiO3/Pt, Pt/PbTiO3/SrRuO3, and SrRuO3/PbTiO3/SrRuO3 models. SrRuO3/PbTiO3/SrRuO3 capacitors with PbO-terminated PbTiO3 layers have a ferroelec. stability similar to that of Pt/PbTiO3/Pt, while the ferroelectricity is strongly suppressed in the capacitors with TiO2-termination. The asym. combination of the electrodes enhances the ferroelec. polarization pointing from SrRuO3 to Pt while the opposite polarization becomes less stable. The epitaxial lattice strain does not strongly affect the electronic Schottky barriers of the sym. capacitors. The contribution of the elec. field originating from the asym. electrodes influences the Schottky barriers significantly. The switching of the polarization in the asym. capacitor changes the Schottky barrier height from PbTiO3 to the SrRuO3 electrode by about 1.0 eV.