2026/07/31 by Adrien Gourgout, Gaël Bastien, Dai Aoki +7
Physics and Astronomy · #cond-mat.str-el #cond-mat.supr-con
14 pages, 12 figures
arxiv created 2026/07/31 · arxiv updated 2026/08/03
We report successive anomalies at low temperature in the magnetic field dependence of the thermoelectric signal in the heavy fermion compound UPd2Al3 inside the antiferromagnetic state up to the metamagnetic transition at HM =18~T. Based on renormalisation perturbation theory and the partitioning of the f orbitals into localized and delocalized parts, our analysis attributes these anomalies to complex topological changes of the Fermi surface driven by Zeeman effect. The observation of a sudden change of sign both in the thermoelectric power and in the Hall coefficient at HM in addition to the appearance of large quantum oscillations in the thermoelectric power above HM indicate a strong Fermi surface reconstruction at the metamagnetic transition due to the unfolding of the electronic bands.