Publikationen
2023
Quasicrystal approximants in the two-dimensional Ba-Ti-O system on Pd(111): A LEED, XPS, and STM study
F. E. Wührl, O. Krahn, S. Schenk, W. Widdra, S. Förster
Physical Review B 107, 195414 (2023)
2022
2D honeycomb transformation into dodecagonal quasicrystals driven by electrostatic forces
S. Schenk, O. Krahn, E. Cockayne, H. L. Meyerheim, M. de Boissieu, S. Förster, W. Widdra
Nature Communications 13, 7542 (2022)
Surface reconstructions on Mn3O4(001) films
K. Gillmeister, M. Trautmann, M. Huth, R. Shantyr, K. Meinel, A. Chassé, K.-M. Schindler, H. Neddermeyer, W. Widdra
Physical Review B 105, 195415 (2022)
Electron pair emission from surfaces: Some general experimental considerations
R. Kamrla, W. Widdra, C.-T. Chiang, F. O. Schumann
J. Elec. Spec. Rel. Phenom. 257, 147185 (2022)
2021
Antiphase Domain Boundary Formation in 2D Ba–Ti–O on Pd(111): An Alternative to Phase Separation
F. E. Wührl, O. Krahn, S. Schenk, S. Förster, W. Widdra
Phys. Status Solidi B, 2100389 (2021)
Plasmonic spin-Hall effect of propagating surface plasmon polaritons in Ni80Fe20 microstructures
M. Paleschke, C.-T. Chiang, L. Brandt, N. Liebing, G. Woltersdorf, W. Widdra
New Journal of Physics 23, 093006 (2021)
Hexagonal approximant of the dodecagonal oxide quasicrystal on Pt(111)
M. Maniraj, L. V. Tran, O. Krahn, S. Schenk, W. Widdra, S. Förster
Physical Review Materials 5, 084006 (2021)
ZnO nucleation into trititanate nanotubes by ALD equipment techniques, a new way to functionalize layered metal oxides
M. Moreno, M. Arredondo, Q. M. Ramasse, M. McLaren, P. Stötzner, S. Förster, E. Benavente, C. Salgado, S. Devis, P. Solar, L. Velasquez, G. González
Scientific Reports 11, 7698 (2021)
Exchange-striction driven ultrafast nonthermal lattice dynamics in NiO
Y. W. Windsor, D. Zahn, R. Kamrla, J. Feldl, H. Seiler, C.-T. Chiang, M. Ramsteiner, W. Widdra, R. Ernstorfer, and L. Rettig, Phys. Rev. Lett. 126, 147202 (2021)
2020
Perfect Monolayers of the BaTiO3-Derived 2D Oxide Quasicrystals Investigated by Scanning Tunneling Microscopy and Noncontact Atomic Force Microscopy
E. M. Zollner, S. Schenk, M. Setvin, S. Förster
Phys. Status Solidi B, 257: 1900620 (2020)
Magnetic Anisotropy in Thin Layers of (Mn,Zn)Fe2O4 on SrTiO3 (001)
R. Denecke, M. Welke, P. Huth, J. Gräfe, K. Brachwitz, M. Lorenz, M. Grundmann, M. Ziese, P. D. Esquinazi, E. Goering, G. Schütz, K.-M. Schindler, A. Chassé
Phys. Status Solidi B, 257: 1900627 (2020)
Nearest Neighbor Distances in SrTiO3 and BaTiO3 from the Projection Analysis of the Extended X-Ray Absorption Fine Structure
A. Bayat, A. Chassé, R. Denecke, S. Förster, P. Huth, E. M. Zollner, K.-M. Schindler
Phys. Status Solidi B, 257: 1900621 (2020)
Surface Stress and Lattice Dynamics in Oxide Ultrathin Films
J. Premper, F. O.Schumann, A. Dhaka, S. Polzin, K. L. Kostov, V. Goian, D. Sander, W. Widdra
Phys. Status Solidi B, 257: 1900650 (2020)
Ultrafast coupled charge and spin dynamics in strongly correlated NiO
K. Gillmeister, D. Golež, C.-T. Chiang, N. Bittner, Y. Pavlyukh, J. Berakdar, P. Werner, W. Widdra
Nature Communications 11, 4095 (2020)
Quasicrystals and their approximants in 2D ternary oxides
S. Förster, S. Schenk, E. M. Zollner, O. Krahn, C.-T. Chiang, F. O. Schumann, A. Bayat, K.-M. Schindler, M. Trautmann, R. Hammer, K. Meinel, W. A. Adeagbo, W. Hergert, J. I. Flege, J. Falta, M. Ellguth, C. Tusche, M. DeBoissieu, M. Muntwiler, T. Gerber, W. Widdra
basic solid state physics, 1900624 (2020)
Laser-based double photoemission spectroscopy at surfaces
C.-T. Chiang, A. Trützschler, M. Huth, R. Kamrla, F. O. Schumann, W. Widdra
Progress in Surface Science 95, 100572 (2020)
From Flat to Tilted: Gradual Interfaces in Organic Thin Film Growth
L. K. Scarbath-Evers, R. Hammer, D. Golze, M. Brehm, D. Sebastiani, W. Widdra
Nanoscale 12, 3834 (2020)
Two-Dimensional wetting layer structures of reduced ternary oxides on Ru(0001) and Pt(111)
E. M. Zollner, F. Schuster, K. Meinel, P. Stötzner, S. Schenk, B. Allner, S. Förster, W. Widdra
basic solid state physics, 1900655 (2020)
2019
Full real-space analysis of a dodecagonal quasicrystal
S. Schenk, E. M. Zollner, O. Krahn, B. Schreck, R. Hammer, S. Förster, W. Widdra
Acta Cryst. A75, 307-313 (2019)
Gold diggers: Altered reconstruction of the gold surface by physisorbed aromatic oligomers
L. K. Scarbath-Evers, M. Todorovic, D. Golze, R. Hammer, W. Widdra, D. Sebastiani, P. Rinke
Phys. Rev. Materials 3, 011601(R) (2019)
SiO2/Si(001) studied by time-resolved valence band photoemission at MHz repetition rates: Linear and nonlinear excitation of surface photovoltage
R. Kamrla, A. Trützschler, M. Huth, C.-T. Chiang, F. O. Schumann, W. Widdra
Journal of Vacuum Science & Technology A 37, 021101 (2019)
Electronic band structure of a two-dimensional oxide quasicrystal
C.-T. Chiang, M. Ellguth, F. O. Schumann, C. Tusche, R. Kraska, S. Förster, W. Widdra
Physical Review B 100, 125149 (2019)
C60 adsorption on a dodecagonal oxide quasicrystal
E. M. Zollner, S. Schenk, S. Förster, W. Widdra
Physical Review B 100, 205414 (2019)
2018
Extended energy range analysis for angle-resolved time-of-flight photoelectron spectroscopy
M. Huth, A. Trützschler, C.-T. Chiang, R. Kamrla, F. O. Schumann, W. Widdra
Journal of Applied Physics 124, 164504 (2018)
Angle-Resolved Photoelectron Spectroscopy at Surfaces with High-Order Harmonic Generation
C.-T. Chiang
Enceclopedia of Interfacial Chemistry, 23-38 (2018)
Ternary Oxide Layers: Novel Crystal Structure Concepts
S. Förster, W. Widdra
Encyclopedia of Interfacial Chemistry, 344-355 (2018)
Growth and lattice dynamics of ultrathin BaO films on Pt(001)
V. Goian, F. O. Schumann, W. Widdra
J. Phys.: Cond. Mat. 30, 095001 (2018)
Image potential states at transition metal oxide surfaces: A time-resolved two-photon photoemission study on ultrathin NiO films
K. Gillmeister, M. Kiel, W. Widdra
Phys. Rev. B 97, 085424 (2018)
Energy shifts in photoemission lines during the tetragonal- to cubic-phase transition in BaTiO3 single crystals and systems with CoFe2O4 and NiFe2O4 overlayers
M. Welke, P. Huth, K. Dabelow, M. Gorgoi, K.-M. Schindler, A. Chassé, R. Denecke
Journal of Physics: Condensed Matter 30, 205401(2018)
2017
Growth and decay of a two-dimensional oxide quasicrystal: High-temperature in situ microscopy
S. Förster, J. I. Flege, E. M. Zollner, F. O. Schumann, R. Hammer, A. Bayat, K. M. Schindler, J. Falta, W. Widdra
Ann. Phys. (Berlin) 529, (1-7) 1600250 (2017)
Light induced degradation of Cu(In,Ga)Se2 thin film surfaces
T. Hölscher, S. Förster, T. Scheider, M. Maiberg, W. Widdra, R. Scheer
App. Phys. Lett. 111, 011604 (2017)
Structure and cation distribution of (Mn0.5Zn0.5)Fe2O4 thin films on SrTiO3(001)
M. Welke, K. Brachwitz, M. Lorenz, M. Grundmann, K.-M. Schindler, A. Chassé, R. Denecke
J. Appl. Phys. 121, 225305-1 - 225305-7 (2017)
Band-resolved double photoemission spectroscopy on correlated valence electron pairs in metals
A. Trützschler, M. Huth, C.-T. Vhiang, R. Kamrla, F. O. Schumann, J. Kirschner, W. Widdra
Phys. Rev. Letters 118, 136401 (2017)
Observation of a dodecagonal oxide quasicrystal and its complex approximant in the SrTiO3-Pt(111) system
S. Schenk, S. Förster, K. Meinel, R. Hammer, B. Leibundgut, M. Paleschke, J. Pantzer, C. Dresler, F. O. Schumann, W. Widdra
J. Phys. Condens. Matter 29, 1-17 (2017)
2016
Mn3O4(001) film growth on Ag(001) - a systematic study using NEXAFS, STM and LEED
K. Gillmeister, M. Huth, R. Shantyr, M. Trautmann, K. Meinel, K.-M. Schindler, H. Neddermeyer, W. Widdra
Surface phonons of NiO(001) ultrathin films grown pseudomorphically on Ag(001)
K. L. Kostov, S. Polzin, F. O. Schumann, W. Widdra
Surface Science 643, 23-29 (2016)
The Kepler tiling as the oldest complex surface structure in history: X-ray structure analyis of a two-dimensional oxide quasicrystal approximant
S. Roy, K. Mohensi, S. Förster, M. Trautmann, F. O. Schumann, E. M. Zollner, H. Meyerheim, W. Widdra
Z. Kristallogr. 231(22), 749-755 (2016)
Surface reconstruction of Pt(001) quantitatively revisited
R. Hammer, K. Meinel, O. Krahn, W. Widdra
Phys. Rev. B 94, 195406-1 - 195406-11 (2016)
NiO growth on Ag(001): A layer-by-layer vibrational study
K. L. Kostov, F. O. Schumann, S. Polzin, D. Sander, W. Widdra
Phys. Rev. B 94, 075438-1 - 075438-10 (2016)
Observation and Structure Determination of an Oxide Quasicrystal Approximant
S. Förster, M. Trautmann, S. Roy, W. A. Adeagbo, E. M. Zollner, R. Hammer, F. O. Schumann, K. Meinel, S. K. Nayak, K. Mohseni, W. Hergert, H. L. Meyerheim, W. Widdra
Phys. Rev. Letters 117, 095501-1 - 095501-5 (2016)
Ultrathin Perovskites: From Bulk Structures to New Interface Concepts
S. Förster, W. Widdra
Oxide Materials at the Two-Dimensional Limit 234, 361-380 (2016)
2015
Domain imaging on multiferroic BiFeO3(001) by linear and circular dichroism in threshold photoemission
A. Sander, M. Christl, C.-T. Chiang, M. Alexe, W. Widdra
Applied Physics 118, 224102-1 - 224102-7 (2015)
Boosting laboratory photoelectron spectroscopy by megahertz high-order harmonics
C.-T. Chiang, M. Huth, A. Trützschler, M. Kiel, F. O. Schumann, J. Kirschner, W. Widdra
New Journal of Physics 17, 13035 (2015)
Efficient and tunable high- order harmonic light sources for photoelectron spectroscopy at surfaces
C.-T. Chiang, M. Huth, A. Trützschler, F. O. Schumann, J. Kirschner, W. Widdra
Electron Spectroscopy and Related Phenomena 200, 15-21 (2015)
2014
Polymer adsorption on reconstructed Au(001): A statistical description of P3HT by scanning tunneling microscopy and coarse-grained Monte Carlo simulations
S. Förster, E. Kohl, M. Ivanov, J. Gross, W. Widdra, and W. Janke
J. Chem. Phys. 141, 164701-1 (2014)
Mosaic and facet structures of epitaxial MnO films on Au(110)
K. Meinel, M. Huth, H. Beyer, H. Neddermeyer, and W. Widdra
Surface Science 619, 83-9 (2014)
Surface reconstruction of Au(001): High- resolution real- space and reciprocal- space inspection
R. Hammer, A. Sander, S. Förster, M. Kiel, K. Meinel, and W. Widdra
Phys. Rev. B 90, 035446 (2014)
Structure of single polythiophene molecules on Au(001) prepared by in-situ UHV electrospray deposition
S. Förster and W. Widdra
J. Chem. Phys. 141, 054713 (2014)
Atomic line emission and high-order harmonic generation in argon driven by 4-MHz μJ laser pulses
A. Blättermann, C.-T. Chiang, and W. Widdra
Physical Review A 89, 043404 (2014)
Electron pair emission detected by time-of-flight spectrometers: new perspectives
M. Huth, C. T. Chiang, A. Trützschler, F. O. Schumann, J. Kirschner, and W. Widdra Applied Physics Letters 104, 061602 (2014)
Thermally and photoinduced polymerization of ultrathin sexithiophene films
A. Sander, R. Hammer, K. Duncker, S. Förster, and W. Widdra
J. Chem. Phys. 141, 104704 (2014)
2013
Quasicrystalline structure formation in a classical crystalline thin-film system
S. Förster, K. Meinel, R. Hammer, M. Trautmann, and W. Widdra
Nature 502, 215-8(2013)
Synthesis of CuCorePtShell nanoparticles as model structures for core-shell electrocatalysts by direct platinum electrodeposition on copper
C. Kulp, K. Gillmeister, W. Widdra, and M. Bron
Chem. Phys. Chem. 14, 1205 (2013)
Surface-phonon dispersion of a NiO(100) thin film
K. L. Kostov, S. Polzin, S. K. Saha, O. Brovko, V. Stepanyuk, and W. Widdra
Physical Review B 87, 235416 (2013)
Tuning the switching time of BiFeO3 capacitors by electrodes’ conductivity
E. J. Guo, A. Herklotz, R. Roth, M. Christl, S. Das, W. Widdra, and K. Dörr
Applied Physics Letters 103, 022905 (2013)
2012
Persistence of surface domain structures for a bulk ferroelectric above TC
A. Höfer, M. Fechner, K. Duncker, M. Hölzer, I. Mertig, and W. Widdra
Phys. Rev. Lett. 108, 087602 (2012)
Improved extraction of I-V curves from low-energy electron diffraction images
K.-M. Schindler, M. Huth, and W. Widdra
Chem. Phys. Lett. 532, 116 (2012)
Oxygen-deficient ordered phases of ultrathin BaTiO3 films on Pt(111)
S. Förster, K. Meinel, K.-M. Schindler, and W. Widdra
Surf. Interface Anal. 44, 628 (2012)
High-order harmonic generation at 4MHz as a light source for time-of-flight photoemission spectroscopy
C.-T. Chiang, A. Blättermann, M. Huth, J. Kirschner, and W. Widdra
Applied Physics Letters 101, 071116 (2012)
Momentum-resolved lifetimes of image-potential states on Ag(001)
K. Duncker, M. Kiel, and Wolf Widdra
Surface Science 606, L87–L90 (2012)
2011
Adsorption of α-sexithiophene on Au(001): Molecule-induced partial lifting of the substrate reconstruction
A. Höfer, K. Duncker, M. Kiel, S. Wedekind and W. Widdra
Physical Review B 83, 075414 (2011)
Laser-excited PEEM using a fully tunable fs-laser system
A. Hofer, K. Duncker, M. Kiel, S. Förster, W. Widdra
IBM Journal of Research and Development, IBM J. Res. Dev. 55, 4:1 (2011)
High-resolution phonon study of the Ag(100) surface
K. L. Kostov, S. Polzin, and W. Widdra
Journal of Physics: Condensed Matter 23, 484006 (2011).
Epitaxial BaTiO3(100) films on Pt(100): A LEED, STM, and XPS study
S. Förster, M. Huth, K.-M. Schindler, and W. Widdra
J. Chem. Phys. 135, 104701 (2011)
2010
Vibrational characterization of ethylene adsorption and its thermal evolution on Si(001)-(2X1): Identification of majority and minority species
L. K. Kostov, R. Nathaniel, T. Mineva, and W. Widdra
The Journal of chemical physics 133, 054705 (2010)
Growth, structure, and thermal stability of epitaxial BaTiO3 films on Pt(111)
S. Förster and W. Widdra
Surface Science 604 2163–2169 (2010)
Thickness dependent vibrational and electronic properties of MnO(100) thin films grown on Pt(111)
S. Sachert, S. Polzin, K. Kostov, and W. Widdra
Physical Review B 81, 195424 (2010)
2009
Low-energy electron diffraction structure determination of an ultrathin CoO film on Ag(001)
K.-M. Schindler , J. Wang, A. Chassé, H. Neddermeyer, and W. Widdra
Surface Science 603, 2658-2663 (2009)
2008
Auger electron diffraction in thin CoO films on Au(111)
A. Chassé, L. Niebergall, M. Heiler, H. Neddermeyer, and K.-M. Schindler
Surf. Sci., 602, 443-51 (2008)
Commensurate surface structures and concerted cis-trans-isomerization within ordered monolayers of alpha-sexithiophene on Ag(001)
K. Duncker, M. Kiel, A. Höfer, and W. Widdra
Phys. Rev. B, 77, 155423-8 (2008)
Growth, atomic structure and vibrational properties of MnO ultrathin films on Pt(111)
C. Hagendorf, S. Sachert, B. Bochmann, K.L. Kostov, and W. Widdra
Phys. Rev. B, 77, 075406 (2008)
2007
Vibrational characterization of different benzene phases on flat and vicinal Si(100) surfaces
B. Naydenov and W. Widdra
J. Chem. Phys. 127, 154711 (2007)
Activation and isomerization of n-butane on sulfated zirconia model systems - An integrated study across the materials and pressure gaps
C. Breitkopf, H. Papp, X. Li, R. Olindo, J. A. Lercher, R. Lloyd, S. Wrabetz, F. C. Jentoft, K. Meinel, S. Förster, K.-M. Schindler, H. Neddermeyer, W. Widdra, A. Hofmann, and J. Sauer
Phys. Chem. Chem. Phys. 9, 1-19 (2007)
Molecular structure and chiral separation in α-sexithiophene ultrathin films on Au(111): Low-energy electron diffraction and scanning tunneling microscopy
M. Kiel, K. Duncker, S. Förster, C. Hagendorf, and W. Widdra
Phys. Rev. B, 1593-1600 (2007)
2006
Two bonding configurations of acetylene on Si(001)-(2x1): A combined HREELS and DFT study
T. Mineva, R. Nathaniel, K.L. Kostov, and W. Widdra
Journal of Chemical Physics 125, 194712-1 -12 (2006)
Interaction of SO3 with c-ZrO2 (111) films on Pt(111)
K. Meinel, A. Hofmann, S. Förster, R. Kulla, K.-M. Schindler, H. Neddermeyer, J. Sauer, and W. Widdra
Phys. Chem. Chem. Phys. 8, 1593-1600 (2006)
Lateral interactions and nonequilibrium in adsorption and desorption. 1. Experimental results for (2x2)-(3O + NO)/Ru(001)
K. L. Kostov, M. Gsell, W. Widdra, S. H. Payne, H. J. Kreuzer, and D. Menzel
Surface Science, 4650 (2006)
Surface and interface structures of epitaxial ZrO2 films on Pt(111)
K. Meinel, A. Eichler, S. Förster, K.-M. Schindler, H. Neddermeyer, and W. Widdra
Phys. Rev. B 74, 235444 (2006)
Charging Mechanisms of Trapped Element-Selectively Excited Nanoparticles Exposed to Soft X Rays
M. Grimm, B. Langer, S. Schlemmer, T. Lischke, U. Becker, W. Widdra, D. Gerlich, R. Flesch, and E. Rühl
Phys. Rev. Lett. 96, 066801-4 (2006)
Pressure-dependent Ni-O phase transitions and Ni oxide formation on Pt(111): An in-situ STM study at elevated temperatures
C. Hagendorf, R. Shantyr, H. Neddermeyer, and W. Widdra
Phys. Chem. Chem. Phys. 8, 1575-83 (2006)
2005
Anisotropy in ordered sexithiophene thin films studied by angle-resolved photoemission using combined laser and synchrotron radiation
C. E. Heiner, J. Dreyer, I. V. Hertel, N. Koch, H.-H. Ritze, W. Widdra, and B. Winter
Appl. Phys. Lett., 87, 093501-3 (2005)
Photoelectron Spectroscopy on Thin Films of Extended Zinc Porphyrazines
D. Pop, B. Winter, W. Freyer, W. Widdra, and I. V. Hertel
Journal of Physical Chemistry B, 109, 7826 -33 (2005)
2004
Charge Carrier Dynamics at the SiO2/Si(100) Surface: A Time-Resolved Photoemission Study with Combined Laser and Synchrotron Radiation
D. Bröcker, T. Gießel, and W. Widdra
Chemical Physics 299, 247-51 (2004)
Scanning tunneling microscopy, spectroscopy and tunneling-induced light emission on donor-doped BaTiO3
T. Doege, C. Hagendorf, and H. Neddermeyer
Surface Science 566-568, 1211-16 (2004)
New Setup To Study Trapped Nano-Particles Using Synchrotron Radiation
M. Grimm, B. Langer, S. Schlemmer, T. Lischke, W. Widdra, D. Gerlich, U. Becker, and E. Rühl
AIP Conference Proceedings, Atomic, Molecular and Chemical Physics 705, 1062-65 (2004)
Vibrational properties and lateral interactions of the (2x2)-(O+CO) coadsorbate layer on Ru(001)
K. L. Kostov, W. Widdra, and D. Menzel
Journal of Physical Chemistry 108, 14324 - 31 (2004)
Hydrogen on Ru(001) revisited: Vibrational structure, adsorption states, and lateral coupling
K. L. Kostov, W. Widdra, and D. Menzel
Surface Science 560, 130-44 (2004)
Comparison of structural re-organisations observed on pre-patterned vicinal Si(1 1 1) and Si(1 0 0) surfaces during heat treatment
A. Kraus, H. Neddermeyer, W. Wulfhekel, D. Sander, T. Maroutian, F. Dulot, A. Martinez-Gil, and M. Hanbucken
Applied Surface Science 234, 307-12 (2004)
STM, LEED, and DFT characterization of epitaxial ZrO2 films on Pt(111)
K. Meinel, A. Eichler, K.-M. Schindler, and H. Neddermeyer
Surface Science 562, 204-18 (2004)
Photoelectron Spectroscopy on Thin Films of Extended Copper Porphyrazines
D. Pop, B. Winter, W. Freyer, R. L. Weber, W. Widdra, and I. V. Hertel
Journal of Physical Chemistry B 108, 9158-67 (2004)
Scanning tunneling microscopy and spectroscopy studies on structural and electronic properties of thin films of Co oxides and oxide precursor states on Ag(001)
R. Shantyr, C. Hagendorf, and H. Neddermeyer
Thin Solid Films 464-465, 65-75 (2004)
Scanning tunneling microscopy and spectroscopy of CoO precursor and oxide layers on Ag(001)
R. Shantyr, C. Hagendorf, and H. Neddermeyer
Surface Science 566-568, 68-73 (2004)
Growth Mechanism and Angle-Resolved Photoemission Spectra of Cobalt Oxide (CoO) Thin Films on Ag(100)
S. Sindhu, M. Heiler, K.-M. Schindler, W. Widdra, and H. Neddermeyer
Surface Science 566-568, 471-75 (2004)
Photoemission from aqueous Alkali-metal-Iodide salt solutions using EUV synchrotron radiation
R. L. Weber, B. Winter, P. M. Schmidt, W. Widdra, I. V. Hertel, M. Dittmar, and M. Faubel
Journal of Physical Chemistry 108, 4729-36 (2004)
Full Valence Band Photoemission from Liquid Water Using EUV Synchrotron Radiation
B. Winter, R. L. Weber, W. Widdra, M. Dittmar, and M. Faubel
Journal of Physical Chemistry A 108, 2625-32 (2004)