In a recent study, scientists from the Max Planck Institute for Chemical Physics of Solids in Dresden have performed a comprehensive study of thermoelectric and thermomagnetic properties of polycrystalline Weyl semimetal NbP.
Die drei Dresdner Max-Planck-Institute – das MPI für die Chemische Physik fester Stoffe, das MPI für die Physik komplexer Systeme und das MPI für molekulare Zellbiologie und Genetik – organisieren eine gemeinsame Veranstaltung zum bundesweiten „Max-Planck-Tag“ in der Dresdner Innenstadt, genauer gesagt im Plenarsaal des Rathauses, um die Arbeit speziell ihrer Institute den Dresdnern und ihren Gästen zu präsentieren.[more]
Magneto-transport experiments of GdPtBi show anomalous Hall effect, chiral anomaly effect and non-zero Berry phase which establish the properties of Weyl physics. All these properties are independent of crystallographic directions. This study confirm that magnetism plays a major role in creating Weyl Fermions via exchange splitting of bands in GdPtBi.
Scientists at the Max Planck Institute Chemical Physics of Solids have written a review paper about magnetic topological materials in the family of Heusler compounds. The review explains the connection between topology, symmetry and magnetism at a level suitable for undergraduate students in physics, chemistry and materials science with a basic knowledge of condensed matter physics.
Scanning tunneling spectroscopy data on the archetypical heavy fermion metal YbRh2Si2 establish a hierarchy of energy scales, with the dominance of the lattice Kondo effect requiring temperatures well (about an order of magnitude) below the single-ion Kondo temperature of about 25 K. Only if the lattice Kondo correlations are sufficiently established, quantum critical fluctuations can evolve.
Topology is a global aspect of materials, leading to fundamental new properties for compounds with large relativistic effects. The incorporation of heavy elements give rise to non-trivial topological phases of matter, such as topological insulators, Dirac and Weyl semimetals. The semimetals are characterized by band-touching points with linear dispersion, similar to massless relativistic particles in high energy physics.
The mechanism behind the observed sample dependency in the heavy-fermion superconductor UBe13 was attributed to the presence of Al impurities in single-crystals. Various diffraction and spectroscopy techniques as well as transmission electron microscopy revealed the location of Al in the structure and its influence on the superconducting properties. Upon long-term annealing, Al atoms can leave the crystal and restore the properties of Al-free UBe13.
A thorough experimental characterization with a theoretical analysis of the chemical bonding of the intermetallic compound MnSiPt leads to surprising results: the formation of direct Mn–Mn bonds is suppressed because the energy gain due to bond formation is significantly smaller than the on-site magnetic interactions. Therefore, after formation of the covalent bonds between Pt and Si as well as between Mn and Si, the strong Mn intra-atomic exchange is the key factor for the stability of the crystal structure. In competition against the Mn–Mn bond formation, intra-atomic magnetic interactions determine the topology of the local atomic arrangement in the finally adopted TiNiSi-type crystal structure in MnSiPt.