Uli Zeitler, HFML Nijmegen. The fractional quantum Hall effect (FQHE), observed in low-temperature magnetotransport experiments in two-dimensional (2D) electron systems and caused by the electron-electron interaction, can be regarded as an ultimate proof of device quality in terms of quantum mobility, homogeneity, and low residual impurities. Until recently, the observation [...]

Sergei Zvyagin, HLD Dresden. Spin systems with honeycomb structures are attracting a great deal of attention, in particular in connection with the famous Kitaev-Heisenberg model. This model predicts a variety of magnetic phases, ranging from the conventional Néel state to a quantum spin liquid, with the spin dynamics determined [...]

William Knafo, LNCMI-Toulouse, Shingo Araki, Okayama University, and Daniel Braithwaite, CEA-Grenoble. The mystery of the hidden-order (HO) phase in the correlated electron paramagnet URu2Si2 is still unsolved. To address this problem, one strategy is to search for clues in the subtle competition between this state and neighboring magnetically ordered [...]

A. Akrap, University of Fribourg, A. V. Pronin, Universität Stuttgart, and M. Orlita, LNCMI-Grenoble.  Experiments have demonstrated many gapless electronic phases with conical bands. These phases exist within diverse classes of systems comprising graphene and many different topological materials. Low-energy excitations in such conical bands somewhat resemble truly relativistic [...]

Owen Moulding and Sven Friedemann, University of Bristol.  TiSe2 features a charge density wave (CDW) driven by condensation of excitons, i.e., pairs of electrons and holes, alongside electronphonon coupling. The CDW transition at 202 K gaps out most of the Fermi surface. Quantum-oscillation measurements at the HFML Nijmegen provide [...]

Matthew Bristow, Amalia Coldea, University of Oxford and William Knafo, LNCMI-Toulouse. CaKFe4As4 belongs to a new family of 1144 iron-based superconductors. It is a clean and stoichiometric superconductor with a relatively high critical temperature of 35 K. This system lacks long-range magnetic order or a nematic electronic state at [...]

S. Kasahara, Kyoto University, N. Hussey, HFML Nijmegen, and J. Wosnitza, HLD Dresden. Superconductivity is destroyed at high magnetic fields. Usually, the highest field up to which this state can exist is the Pauli paramagnetic limit, when the Zeeman energy of the itinerant electrons becomes larger than the superconducting [...]

Hans Engelkamp and Peter Christianen, HFML Nijmegen. This research shows that magnetic levitational bioassembly with a non-toxic, low concentration of a paramagnetic medium in high magnetic field is technologically feasible. Moreover, the experimental results confirm that it can be used as a cost-effective alternative to microgravity research at the [...]

Alexandre Pourret, CEA Grenoble and Gabriel Seyfarth, LNCMI-Grenoble. The recently discovered heavy-fermion superconductor UTe2 with superconducting transition temperature of 1.6 K is one of the rare examples of a heavy-fermion material with superconductivity appearing above 1 K. In contrast to the ferromagnetic heavy-fermion superconductors UCoGe and URhGe, UTe2 is [...]

Denis Gorbunov, HLD Dresden. The physical properties of uranium-based intermetallic compounds depend strongly on the degree of localization of the 5f electrons. The extended character of the 5f states leads to a high sensitivity to external parameters. The pronounced spin-orbit interaction of uranium provides significant orbital polarization of the [...]