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DF: Fachverband Dielektrische Festkörper
DF 2: Nonlinear dielectrics, phase transitions, relaxors
DF 2.5: Vortrag
Montag, 14. März 2011, 12:20–12:40, KÖN Farb
Complex polarization ordering in PbTiO3 nanowires: A first-principles computational study — Ghanshyam Pilania1 and •Rampi Ramprasad2 — 1University of Connecticut, Storrs, USA — 2University of Connecticut, Storrs, USA; Fritz-Haber-Institut der MPG, Berlin, Germany
Based on parameter-free density-functional-theory calculations, we demonstrate the possibility of nonrectilinear curling vortex electric dipole configurations in PbTiO3 nanowires [1]. We predict that the critical size for the genesis of the vortex polarization instability with an axial toroidal moment is 16 Å. We also report previously unknown phase transitions between the nonrectilinear vortex and conventional rectilinear axial polarization configurations mediated by strain and surface terminations. The ability to switch reversibly between the vortex clockwise/counterclockwise and axial positive/negative polarization states may open up transformative technological possibilities.
[1] G. Pilania and R. Ramprasad, Phys. Rev. B 82, 155442 (2010).