Publications

Order by: publication date number of citations

• In-plane Fermi surface mapping of ZrSiS and HfSiS by de Haas-van Alphen oscillations

  Bruno Gudac, Mihovil Bosnar, Filip Orbanić, Trpimir Ivšić, Ivan Kokanović, Mario Novak

  SciPost Phys. Proc. 11, 019 (2023) · published 6 June 2023 | Toggle abstract · pdf

  We have conducted a comprehensive experimental investigation of the in-plane de Haas van Alphen quantum oscillations in ZrSiS and HfSiS and compared the results to the ab-initio calculations. We found a moderately good agreement for a set of frequencies located between 100 T and 200 T. These could be associated with extremal orbitals of the electron pockets located around the $k_z=\pm\pi/2c$ planes at the edge of the 1st Brillouin zone. In contrast, the experimentally detected low-frequency set of oscillations found around 20 T could not be reproduced by the calculations. Further refinement of the ab-initio calculation has to be conducted to fully capture all the observed features of the Fermi surface in ZrSiS and HfSiS.

• Composition dependence of the specific heat of FeSi

  Carolina Burger, Andreas Bauer, Christian Pfleiderer

  SciPost Phys. Proc. 11, 020 (2023) · published 6 June 2023 | Toggle abstract · pdf

  Recently, a high-mobility surface conduction channel and in-gap states were identified in the correlated small-gap semiconductor FeSi using electrical transport measurements and high-resolution tunneling spectroscopy. The mobility of the charge carriers in the surface channel is quantitatively reminiscent of topological insulators, but displays a lack of sensitivity to the presence of ferromagnetic impurities as studied by means of a series of single crystals with slightly different starting compositions. Here, we report measurements of the specific heat of these crystals. At low temperatures, a shallow maximum is observed in the specific heat divided by temperature. This maximum is suppressed under magnetic field, characteristic of a Schottky anomaly associated with magnetic impurities. In comparison, the height of this maximum decreases with increasing initial iron content.

• Magnetic, electronic, and structural investigation of the strongly correlated Y$_{1-x}$Sm$_{x}$Co$_5$ system

  F. Passos, D. Cornejo, G. J. Nilsen, V. Martelli, J. Larrea Jiménez

  SciPost Phys. Proc. 11, 021 (2023) · published 6 June 2023 | Toggle abstract · pdf

  SmCo$_5$ and YCo$_5$ are isostructural compounds both showing large magnetocrystalline anisotropy, where the former originates mainly from the crystal-electric field and magnetic interactions. We investigate the contribution of both interactions by partially substituting Y by Sm in as-cast polycrystalline Y$_{1-x}$Sm$_{x}$Co$_5$ (with $x$=0.00, 0.12, 0.18, 0.31, and 0.40) and measuring their structural, magnetic, and electrical properties through X-ray diffraction, magnetization, and electrical transport measurements. Our results suggest an interplay between microstructure strain in as-cast samples and the electronic and magnetic interactions.

• Dark matter searches and energy accumulation and release in materials

  Sergey Pereverzev

  SciPost Phys. Proc. 12, 009 (2023) · published 3 July 2023 | Toggle abstract · pdf

  Efforts to identify dark matter by detecting nuclear recoils produced by dark matter particles reveal low-energy backgrounds of unknown origin in different types of detectors. In many cases, energy accumulation and delayed burst-like releases of stored energy could provide an explanation. These dynamics follow Prigogine's ideas on systems with energy flow and the general Self-Organized Criticality scenario. We compare these models with properties of excess backgrounds in cryogenic solid-state detectors, relaxation processes in glasses and crystals, our observations of delayed luminescence in NaI(Tl), and make predictions for more phenomena present in these systems and in superconducting photon detectors and qubits. Experiments to create accurate phenomenological models are needed.