Defects; Ferroic; Scanning probe microscopy; Skyrmions; Oxides; Domain walls
SchaabJ., ShapovalovK., SchoenherrP., HacklJ., KhanI., HentschelM., YanZ., BourretE., SchneiderC.M., NemsakS., StengelM., CanoA., MeierD. (2019), Electrostatic potential mapping at ferroelectric domain walls by low-temperature photoemission electron microscopy, in Appl. Phys. Lett.
, 115 (2019)(122903), 122903.
Schoenherr Peggy, Shapovalov Konstantin, Schaab Jakob, Yan Zewu, Bourret Edith D., Hentschel Mario, Stengel Massimiliano, Fiebig Manfred, Cano Andrés, Meier Dennis (2019), Observation of Uncompensated Bound Charges at Improper Ferroelectric Domain Walls, in Nano Letters
, 19(3), 1659-1664.
Schaab Jakob, Skjærvø Sandra H., Krohns Stephan, Dai Xiaoyu, Holtz Megan E., Cano Andrés, Lilienblum Martin, Yan Zewu, Bourret Edith, Muller David A., Fiebig Manfred, Selbach Sverre M., Meier Dennis (2018), Electrical half-wave rectification at ferroelectric domain walls, in Nature Nanotechnology
, 13(11), 1028-1034.
Schoenherr P., Müller J., Köhler L., Rosch A., Kanazawa N., Tokura Y., Garst M., Meier D. (2018), Topological domain walls in helimagnets, in Nature Physics
, 14(5), 465-468.
HolstadT.S., EvansD.M., RuffA., SmåbråtenD.R., SchaabJ., TzschaschelCh., YanZ., BourretE., SelbachS.M., KrohnsS., MeierD. (2018), Electronic bulk and domain wall properties in B-site doped hexagonal ErMnO3, in Phys. Rev. B
, 97, 085143.
MeierDennis (2017), Walls with special functionality, in Physik Journal
, (9), 55-55.
Mundy J. A., Schaab J., Kumagai Y., Cano A., Stengel M., Krug I. P., Gottlob D. M., Doğanay H., Holtz M. E., Held R., Yan Z., Bourret E., Schneider C. M., Schlom D. G., Muller D. A., Ramesh R., Spaldin N. A., Meier D. (2017), Functional electronic inversion layers at ferroelectric domain walls, in Nature Materials
, 16(6), 622-627.
Ruff E., Krohns S., Lilienblum M., Meier D., Fiebig M., Lunkenheimer P., Loidl A. (2017), Conductivity contrast and tunneling charge transport in the vortex-like ferroelectric domain pattern of multiferroic hexagonal YMnO3, in Physical Review Letters
, 118, 036803.
Mundy J., Schaab J., Kumagai Y., Cano A., Stengel M., Krug I. P., Gottlob D. M., Doganay H., Holtz M. E., Held R., Yan Z., Bourret E., Schneider C. M., Schlom D. G., Muller D. A., Ramesh R., Spaldin N. A., Meier D. (2017), Functional electronic inversion layers at ferroelectric domain walls, in Nature Materials
, 16, 622-627.
Schaab J., Krug I. P., Doganay H., Hackl J., Gottlob D., Khan M. I., Nemsak S., Maurel L., Langenberg E., Algarabel P. A., Pardo J. A., Schneider C. M., Meier D. (2016), Contact-Free Mapping of Electronic Transport Phenomena of Polar Domains in SrMnO3 Films, in Phys. Rev. Appl.
, 5, 054009.
Dussaux A., Schoenherr P., Koumpouras K., Chico J., Chang K., Lorenzelli L., Kanazawa N., Tokura Y., Garst M., Bergman A., Degen C. L., Meier D. (2016), Local dynamics of topological magnetic defects in the itinerant helimagnet FeGe, in Nature Communications
, 7, 12430.
Schaab J., Cano A., Lilienblum M., Yan Z., Bourret E., Ramesh R., Fiebig M., Meier D. (2016), Optimization of electronic domain-wall properties by aliovalent cation substitution, in Advanced Electronic Materials
, 2, 1500195.
Hassanpour E., Wegmayr V., Schaab J., Yan Z., Bourret E., Lottermoser Th., Fiebig M., Meier D. (2016), Robustness of magnetic and electric domains against charge carrier doping in multiferroic hexagonal ErMnO3, in New Journal of Physics
, 18, 43015.
Schaab J., Trassin M., Scholl A., Yan Z., Bourret E., Ramesh R., Meier D. (2015), Ferroelectric domains in the multiferroic phase of ErMnO3 imaged by low-temperature, in Journal of Physics: Conference Series
, 592, 012120.
Yan Z., Meier D., Schaab J., Ramesh R., Samulon E., Bourret E. (2015), Growth of high-quality hexagonal ErMnO3 single crystals by the pressurized floating-zone method, in Journal of Crystal Growth
, 409, 75-79.
Leo N., Bergman A., Cano A., Poudel N., Lorenz B., Fiebig M., Meier D. (2015), Polarization control at spin-driven ferroelectric domain walls, in Nature Communications
, 6, 6661.
Becher C., Maurel L., Aschauer U., Lilienblum M., Magen C., Meier D., Langenberg E., Trassin M., Balsco J., Krug I. P., Algarabel P. A., Spaldin N. A., Pardo J. A., Fiebig M. (2015), Strain-induced coupling of electrical polarization and structural defects in SrMnO3 films, in Nature Nanotechnology
, 10, 661-665.
Modern electronics devices greatly benefit from the fascinating physics that occur when tailored defects are introduced into an otherwise perfectly ordered crystal structure. This is strikingly reflected by p- and n-type semiconductors that basically owe all their special properties to charge transfer from implanted defects known as acceptor and donor atoms, respectively. Another type of engineered defect with functional qualities are hetero-interfaces at which two different materials meet with atomic precision. At the LaAlO3/SrTiO3 interface, for instance, unique electric transport properties arise that drastically differ from those of the surrounding bulk material. A major drawback of the aforementioned type of chemical impurity or artificial interface is that they are passive defects: once implemented into a material it is difficult or even impossible to move or otherwise manipulate them later on. In a very recent development attempts are made to overcome this fundamental limitation and identify systems with active defects, i.e., defects of a type that can be readily manipulated post-growth. This may, for example, be a domain wall which, due to the confinement and discontinuity at the wall, can have transport or magnetic properties that are very different from those of the bulk: In contrast to the immobile interface separating constituents in a heterostructure a domain wall can be created, annihilated, or moved at any time by an appropriate external force field.In our project we will focus on the investigation of two types of active defects of great current interest: (i) domain walls in multiferroics with improper ferroelectricity; (ii) topological magnetic vortices of spins, called skyrmions, in half-metals and insulators. These two types of defects are of the two- and one-dimensional type, respectively, and outstanding because of an intriguing interplay of magnetic and electric degrees of freedom inherent to them. The extraordinary potential of domain walls and skyrmions as active low-dimensional building blocks for nano-electronics has been realized so very recently that their understanding is still at a fragmentary level and their occurrence limited to cryogenic temperatures. We will now apply a unique combination of state-of-the-art low-temperature scanning probe microscopy (SPM) techniques for gaining a comprehensive picture of magnetic and electric defect properties at the level of the inherent length scale (~20 nm) of these low-dimensional objects. We will thus achieve a fundamental understanding of the complex correlation physics associated to multiferroic domain walls and skyrmions as well as their manipulation as "active defects". Note that this submission is the first part of a tandem proposal: The SPM laboratory constituting the experimental center of our project will be applied for via the R'Equip program (deadline 15 May 2013) while the present project proposal covers funding for the remaining equipment, consumables, personnel, and traveling. Both parts are submitted under the same title.