Daniel Wortmann

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We report on the epitaxial fabrication and electronic properties of a topological phase in strained α-Sn on InSb. The topological surface state forms in the presence of an unusual band order not based on direct spin-orbit coupling, as shown in density functional and GW slab-layer calculations. Angle-resolved photoemission including spin detection probes(More)
In many scientific applications the solution of non-linear differential equations are obtained through the set-up and solution of a number of successive eigenproblems. These eigenproblems can be regarded as a sequence whenever the solution of one problem fosters the initialization of the next. In addition, some eigenproblem sequences show a connection(More)
The spin-polarized scanning tunneling microscope (SP-STM) operated in the constant current mode is proposed as a powerful tool to investigate complex atomic-scale magnetic structures of otherwise chemically equivalent atoms. The potential of this approach is demonstrated by successfully resolving the magnetic structure of Cr/Ag(111), which is predicted on(More)
A half-metal has been defined as a material with propagating electron states at the Fermi energy only for one of the two possible spin projections, and as such has been promoted as an interesting research direction for spin electronics. This review details recent advances on manganite thin film research within the field of spintronics, before presenting the(More)
We present an efficient method for calculating the conductance of ballistic electrons through an interface from first principles using the embedding approach of Inglesfield. In our method the Landauer-Büttiker formula for ballistic transport is expressed in terms of two quantities that are available in the embedded Green-function formalism without(More)
The properties that distinguish topological crystalline insulator (TCI) and topological insulator (TI) rely on crystalline symmetry and time-reversal symmetry, respectively, which encodes different bulk and surface/edge properties. Here, we predict theoretically that electron-doped TlM (M = S and Se) (110) monolayers realize a family of two-dimensional (2D)(More)
Electrons mediate many of the interactions between atoms in a solid. Their propagation in a material determines its thermal, electrical, optical, magnetic and transport properties. Therefore, the constant energy contours characterizing the electrons, in particular the Fermi surface, have a prime impact on the behaviour of materials. If anisotropic, the(More)
T. Ohwaki,1 D. Wortmann,2 H. Ishida,3 S. Blügel,2 and K. Terakura1,4 1Research Institute for Computational Sciences, AIST, Tsukuba, Ibaraki 306-8568, Japan 2Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany 3CREST, JST, and Nihon University, Sakura-josui, Tokyo 156-8550, Japan 4Creative Research Initiative “Sousei,” Hokkaido(More)
The influence of local Coulomb correlations on the surface electronic structure of SrVO3, a stronglycorrelated metal in a perovskite structure, is investigated for both the SrO-layer and VO2-layer-terminated 001 surfaces. The electronic structure within the local density approximation of a semi-infinite surface is determined using the embedded(More)
c 2006 by John von Neumann Institute for Computing Permission to make digital or hard copies of portions of this work for personal or classroom use is granted provided that the copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise requires prior(More)