• Application of a long short-term memory for deconvoluting conductance contributions at charged ferroelectric domain walls 

      Holstad, Theodor Secanell; Ræder, Trygve Magnus; Evans, Donald; Småbråten, Didrik Rene; Krohns, Stephan; Schaab, Jakob; Yan, Zewu; Bourret, Edith; Helvoort, Antonius T. J. van; Grande, Tor; Selbach, Sverre Magnus; Agar, Joshua; Meier, Dennis Gerhard (Peer reviewed; Journal article, 2020)
      Ferroelectric domain walls are promising quasi-2D structures that can be leveraged for miniaturization of electronics components and new mechanisms to control electronic signals at the nanoscale. Despite the significant ...
    • Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide 

      Evans, Donald; Holstad, Theodor Secanell; Mosberg, Aleksander Buseth; Småbråten, Didrik Rene; Vullum, Per Erik; Dadlani, Anup; Shapovalov, Konstantin; Yan, Zewu; Bourret, Edith; Gao, David Zhe; Akola, Jaakko; Torgersen, Jan; Van Helvoort, Antonius; Selbach, Sverre Magnus; Meier, Dennis (Peer reviewed; Journal article, 2020)
      Utilizing quantum effects in complex oxides, such as magnetism, multiferroicity and superconductivity, requires atomic-level control of the material’s structure and composition. In contrast, the continuous conductivity ...
    • Contact-free reversible switching of improper ferroelectric domains by electron and ion irradiation 

      Roede, Erik Dobloug; Mosberg, Aleksander Buseth; Evans, Donald; Bourret, Edith; Yan, Zewu; Van Helvoort, Antonius; Meier, Dennis (Peer reviewed; Journal article, 2021)
      Focused ion beam (FIB) and scanning electron microscopy (SEM) are used to reversibly switch improper ferroelectric domains in the hexagonal manganite ErMnO3. Surface charging is achieved by local ion (positive charging) ...
    • Domain wall mobility and roughening in doped ferroelectric hexagonal manganites 

      Småbråten, Didrik Rene; Holstad, Theodor Secanell; Evans, Donald; Zewu, Yan; Bourret, Edith; Meier, Dennis; Selbach, Sverre Magnus (Peer reviewed; Journal article, 2020)
      The macroscopic performance of ferroelectric and piezoelectric devices depends strongly on domain wall dynamics. It is clear that structural defects, such as vacancies, interstitials, and dopants codetermine the dynamics, ...
    • Electrical half-wave rectification at ferroelectric domain walls 

      Schaab, Jakob; Skjærvø, Sandra Helen; Krohns, Stephan; Dai, Xiaoyu; Holtz, Megan, E.; Cano, Andrés; Lilienblum, Martin; Yan, Zewu; Bourret, Edith; Muller, David A.; Fiebig, Manfred; Selbach, Sverre Magnus; Meier, Dennis (Journal article; Peer reviewed, 2018)
      Domain walls in ferroelectric semiconductors show promise as multifunctional two-dimensional elements for next-generation nanotechnology. Electric fields, for example, can control the direct-current resistance and reversibly ...
    • Electronic bulk and domain wall properties in B-site doped hexagonal ErMnO3 

      Holstad, Theodor S.; Evans, Donald; Ruff, Alexander; Småbråten, Didrik Rene; Schaab, Jakob; Tzschaschel, Christian; Yan, Zewu; Bourret, Edith; Selbach, Sverre Magnus; Krohns, Stephan; Meier, Dennis (Journal article; Peer reviewed, 2018)
      Acceptor and donor doping is a standard for tailoring semiconductors. More recently, doping was adapted to optimize the behavior at ferroelectric domain walls. In contrast to more than a century of research on semiconductors, ...
    • Electrostatic potential mapping at ferroelectric domain walls by low-temperature photoemission electron microscopy 

      Schaab, Jakob; Shapovalov, Konstantin; Schoenherr, Peggy; Hackl, Johanna; Khan, Muhammad Imtiaz; Hentschel, Mario; Yan, Zewu; Bourret, Edith; Schneider, Claus M.; Nemsak, Slavomír; Stengel, Massimiliano; Cano, Andrés; Meier, Dennis (Journal article; Peer reviewed, 2019)
      Low-temperature X-ray photoemission electron microscopy (X-PEEM) is used to measure the electric potential at domain walls in improper ferroelectric Er0.99Ca0.01MnO3. By combining X-PEEM with scanning probe microscopy and ...
    • FIB lift-out of conducting ferroelectric domain walls in hexagonal manganites 

      Mosberg, Aleksander Buseth; Roede, Erik Dobloug; Evans, Donald; Holstad, Theodor S.; Bourret, Edith; Yan, Zewu; Van Helvoort, Antonius; Meier, Dennis (Journal article; Peer reviewed, 2019)
      A focused ion beam (FIB) methodology is developed to lift out suitable specimens containing charged domain walls in improper ferroelectric ErMnO3. The FIB procedure allows for extracting domain wall sections with well-defined ...
    • FIB lift-out of conducting ferroelectric domain walls in hexagonal manganites 

      Evans, Donald; Meier, Dennis; Mosberg, Aleksander Buseth; Roede, Erik Dobloug; Holstad, Theodor S.; Bourret, Edith; Yan, Zewu; Van Helvoort, Antonius (Journal article; Peer reviewed, 2019)
      A focused ion beam (FIB) methodology is developed to lift out suitable specimens containing charged domain walls in improper ferroelectric ErMnO3. The FIB procedure allows for extracting domain wall sections with well-defined ...
    • Frequency dependent polarisation switching in h-ErMnO3 

      Ruff, Alexander; Li, Ziyu; Loidl, Alois; Schaab, Jakob; Fiebig, Manfred; Cano, Andres; Yan, Zewu; Bourret, Edith; Glaum, Julia; Meier, Dennis; Krohns, Stephan (Journal article; Peer reviewed, 2018)
      We report an electric-field poling study of the geometric-driven improper ferroelectric h-ErMnO3. From a detailed dielectric analysis we deduce the temperature and frequency dependent range for which single-crystalline ...
    • Functional electronic inversion layers at ferroelectric domain walls 

      Mundy, Julia; Schaab, Jakob; Kumagai, Yu; Cano, Andres; Stengel, Massimiliano; Krug, Ingo P.; Gottlob, Daniel G.; Doganay, Hattice; Holtz, Megan, E.; Held, Rainer; Yan, Zewu; Bourret, Edith; Schneider, Claus M.; Schlom, Darrel G.; Muller, David A.; Ramesh, Ramamoorthy; Spaldin, Nicola A.; Meier, Dennis Gerhard (Journal article; Peer reviewed, 2017)
      Ferroelectric domain walls hold great promise as functional two-dimensional materials because of their unusual electronic properties. Particularly intriguing are the so-called charged walls where a polarity mismatch causes ...
    • Global formation of topological defects in the multiferroic hexagonal manganites 

      Meier, Quintin Noel; Lilienblum, Martin; Griffin, Sinead M; Conder, K; Pomjakushina, Ekaterina; Yan, Zewu; Bourret, Edith; Meier, Dennis; Lichtenberg, Frank; Salje, Ekhard K. H.; Spaldin, Nicola A.; Fiebig, Manfred; Cano, Andrés (Journal article; Peer reviewed, 2017)
      The spontaneous transformations associated with symmetry-breaking phase transitions generate domain structures and defects that may be topological in nature. The formation of these defects can be described according to the ...
    • Insulating improper ferroelectric domain walls as robust barrier layer capacitors 

      Puntigam, Lukas; Schultheiss, Jan; Strinic, Ana; Yan, Zewu; Bourret, Edith; Altthaler, Markus; Keszmarki, Istvan; Evans, Donald; Meier, Dennis Gerhard; Krohns, Stephan (Peer reviewed; Journal article, 2021)
      We report the dielectric properties of improper ferroelectric hexagonal (h-)ErMnO3. From the bulk characterization, we observe a temperature and frequency range with two distinct relaxation-like features, leading to high ...
    • Intrinsic and extrinsic conduction contributions at nominally neutral domain walls in hexagonal manganites 

      Schultheiß, Jan; Schaab, Jakob; Småbråten, Didrik Rene; Skjærvø, Sandra Helen; Bourret, Edith; Yan, Zewu; Selbach, Sverre Magnus; Meier, Dennis Gerhard (Peer reviewed; Journal article, 2020)
      Conductive and electrostatic atomic force microscopy (cAFM and EFM) are used to investigate the electric conduction at nominally neutral domain walls in hexagonal manganites. The EFM measurements reveal a propensity of ...
    • Observation of uncompensated bound charges at improper ferroelectric domain walls 

      Schoenherr, Peggy; Shapovalov, Konstantin; Schaab, Jakob; Yan, Zewu; Bourret, Edith; Hentschel, Mario; Stengel, Massimiliano; Fiebig, Manfred; Cano, Andrés; Meier, Dennis (Journal article; Peer reviewed, 2019)
      Low-temperature electrostatic force microscopy (EFM) is used to probe unconventional domain walls in the improper ferroelectric semiconductor Er0.99Ca0.01MnO3 down to cryogenic temperatures. The low-temperature EFM maps ...
    • Topological defects in hexagonal manganites - Inner structure and emergent electrostatics 

      Holtz, Megan, E.; Shapovalov, Konstantin; Mundy, Julia; Chang, C. S.; Yan, Zewu; Bourret, Edith; Muller, David A.; Meier, Dennis; Cano, Andrés (Journal article; Peer reviewed, 2017)
      Diverse topological defects arise in hexagonal manganites, such as ferroelectric vortices, as well as neutral and charged domain walls. The topological defects are intriguing because their low symmetry enables unusual ...