Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Superconductivity: Sample Preparation and Characterization
TT 5.11: Talk
Monday, March 9, 2026, 12:15–12:30, CHE/0089
Multiple superconducting transitions in Yb3+xCo4Sn13−x — •Roman Gumeniuk1, Meret Orlob1, Volodymyr Levytskyi1, Alexander A. Tsirlin2, Bohdan Kundys3, and Andreas Leithe-Jasper4 — 1Institut für Experimentelle Physik, TU Bergakademie Freiberg, 09596 Freiberg, Germany — 2Felix-Bloch-Institut für Festkörperphysik, Universität Leipzig, 04103 Leipzig, Germany — 3Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux, Strasbourg F-67000, France — 4Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden, Germany
Yb3+xCo4Sn13−x is shown to posses homogeneity range within 0≤ x ≤0.5. For all x a primitive cubic [space group Pm3n, a≈9.54 Å] structure of strongly disordered Sc3Ir4Si13+x type is found. Despite showing no signatures of presence of additional phases, different pieces of the same stoichiometric Yb3Co4Sn13 sample revealed multiple superconducting transitions of varying intensity at Tc = 3.1(2) K and Tc = 2.4(2) K in temperature dependence of specific heat. On the other hand, Yb3.2Co4Sn12.8 is found to be a strongly coupled superconductor with single transition at Tc = 2.4(2) K and enhanced critical magnetic field Bc2=4.79(9) T. To shed light on superconducting behaviors in both stannides diverse models were applied to describe Bc2(Tc) and cel(T) dependencies. Both Yb3+xCo4Sn13−x (x=0, 0.2) compounds reveal bosonic peaks in specific heat and thus, possible ‘rattling’ behavior. They are also metallic systems, some aspects of which are described by a free electron gas model [1].
[1] M. Orlob et al., Phys. Rev. B 112 (2025) 174513
Keywords: superconductivity; magnetism; electronic density of state; crystal structure