Enhanced electric conductivity at ferroelectric vortex cores in BiFeO3

T opological defects in ferroic materials are attracting much attention both as a playground of unique physical phenomena and for potential applications in reconfigurable electronic devices. Here, we explore electronic transport at artificially created ferroelectric vortices in BiFeO3 thin films. The creation of one-dimensional conductive channels activated at voltages as low as 1 V is demonstrated. We study the electronic as well as the static and dynamic polarization structure of several topological defects using a combination of first-principles and phase-field modelling. The modelling predicts that the core structure can undergo a reversible transformation into a metastable twist structure, extending charged domain walls segments through the film thickness. The vortex core is therefore a dynamic conductor controlled by the coupled response of polarization and electron‐mobile-vacancy subsystems with external bias. This controlled creation of conductive one-dimensional channels suggests a pathway for the design and implementation of integrated oxide electronic devices based on domain patterning.

[1]  Ivan Naumov,et al.  Vortex-to-polarization phase transformation path in ferroelectric Pb(ZrTi)O3 nanoparticles. , 2007, Physical review letters.

[2]  Stephen Jesse,et al.  The band excitation method in scanning probe microscopy for rapid mapping of energy dissipation on the nanoscale , 2007, 0708.4248.

[3]  N. D. Mermin,et al.  The topological theory of defects in ordered media , 1979 .

[4]  W. Ren,et al.  Chiral patterns of tilting of oxygen octahedra in zero-dimensional ferroelectrics and multiferroics: a first principle-based study. , 2010, Physical review letters.

[5]  Andrei Artemev,et al.  Phase-field modeling of domain structure of confined nanoferroelectrics. , 2008, Physical review letters.

[6]  L. McGilly,et al.  Domain bundle boundaries in single crystal BaTiO3 lamellae: searching for naturally forming dipole flux-closure/quadrupole chains. , 2010, Nano letters.

[7]  Sergei V. Kalinin,et al.  Polarization Control of Electron Tunneling into Ferroelectric Surfaces , 2009, Science.

[8]  A. Tagantsev,et al.  Linear Singularities and Their Motion in Improper Ferroelectrics , 1989 .

[9]  Landau theory of domain wall magnetoelectricity , 2010, 1002.3819.

[10]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[11]  Jeremy Levy,et al.  Oxide Nanoelectronics on Demand , 2009, Science.

[12]  Venkatraman Gopalan,et al.  Static conductivity of charged domain walls in uniaxial ferroelectric semiconductors , 2011, 1103.2745.

[13]  A. Gruverman,et al.  Mesoscale flux-closure domain formation in single-crystal , 2011, Nature communications.

[14]  Jie Wang,et al.  Switching mechanism of polarization vortex in single-crystal ferroelectric nanodots , 2010 .

[15]  Yi Zhang,et al.  Spontaneous vortex nanodomain arrays at ferroelectric heterointerfaces. , 2011, Nano letters.

[16]  M. Alexe,et al.  Nanoscale properties of thin twin walls and surface layers in piezoelectric WO3−x , 2010 .

[17]  B. Noheda,et al.  Conduction through 71° domain walls in BiFeO3 thin films. , 2011, Physical review letters.

[18]  C. Eom,et al.  Tuning the remanent polarization of epitaxial ferroelectric thin films with strain , 2009 .

[19]  E. Dagotto,et al.  Conducting Jahn-Teller domain walls in undoped manganites , 2010, 1005.4918.

[20]  I. Kornev,et al.  Finite-temperature properties of multiferroic BiFeO3. , 2007, Physical review letters.

[21]  U. V. Waghmare,et al.  First-principles study of spontaneous polarization in multiferroic BiFeO 3 , 2005 .

[22]  J. Neaton,et al.  First-principles study of spontaneous polarization in multiferroic BiFeO3 , 2005 .

[23]  H. Christen,et al.  Applying uniform reversible strain to epitaxial oxide films , 2010 .

[24]  Valerii M. Vinokur,et al.  Vortices in high-temperature superconductors , 1994 .

[25]  D. Chu,et al.  Flux closure vortexlike domain structures in ferroelectric thin films. , 2010, Physical review letters.

[26]  A. Bratkovsky,et al.  Vortex polarization states in nanoscale ferroelectric arrays. , 2009, Nano letters.

[27]  Peter Maksymovych,et al.  Dynamic conductivity of ferroelectric domain walls in BiFeO₃. , 2011, Nano letters.

[28]  William T. Lee,et al.  Trapping of oxygen vacancies in the twin walls of perovskite , 2010 .

[29]  Sergei V. Kalinin,et al.  Deterministic control of ferroelastic switching in multiferroic materials. , 2009, Nature nanotechnology.

[30]  B. Gu,et al.  Unusual vortex structure in ultrathin Pb(Zr0.5Ti0.5)O3 films , 2007 .

[31]  James F. Scott,et al.  Physics and Applications of Bismuth Ferrite , 2009 .

[32]  V. Shvartsman,et al.  Anomalous polarization inversion in ferroelectrics via scanning force microscopy , 2007 .

[33]  M. Alexe,et al.  Vortex ferroelectric domains , 2008 .

[34]  Sergei V. Kalinin,et al.  Mesoscopic metal-insulator transition at ferroelastic domain walls in VO2. , 2010, ACS nano.

[35]  Inna Ponomareva,et al.  Original properties of dipole vortices in zero-dimensional ferroelectrics , 2008 .

[36]  E. Salje,et al.  Domain boundary engineering , 2009 .

[37]  L. Eric Cross,et al.  Domains in Ferroic Crystals and Thin Films , 2010 .

[38]  C. Eom,et al.  Ferroelectric domain structure in epitaxial BiFeO3 films , 2005 .

[39]  Sergei V. Kalinin,et al.  Conduction at domain walls in oxide multiferroics. , 2009, Nature Materials.

[40]  Marin Alexe,et al.  Direct Observation of Continuous Electric Dipole Rotation in Flux-Closure Domains in Ferroelectric Pb(Zr,Ti)O3 , 2011, Science.

[41]  P. Muralt,et al.  Polarization reversal due to charge injection in ferroelectric films , 2005 .

[42]  Yi Zhang,et al.  One-dimensional topologically protected modes in topological insulators with lattice dislocations , 2009 .

[43]  Y. Rosenwaks,et al.  Ferroelectric domain engineering using atomic force microscopy tip arrays in the domain breakdown regime , 2005 .

[44]  Shan X. Wang,et al.  Nanoscale control of exchange bias with BiFeO3 thin films. , 2008, Nano letters.