Inhomogeneity-driven multiform Spontaneous Hall Effect in conventional and unconventional superconductors

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Nadia Stegani - , University of Genoa, National Research Council of Italy (CNR) (Author)
  • Ilaria Pallecchi - , National Research Council of Italy (CNR) (Author)
  • Nicola Manca - , National Research Council of Italy (CNR) (Author)
  • Martina Meinero - , University of Genoa, National Research Council of Italy (CNR) (Author)
  • Michela Iebole - , University of Genoa, National Research Council of Italy (CNR) (Author)
  • Matteo Cialone - , University of Genoa, National Research Council of Italy (CNR) (Author)
  • Valeria Braccini - , National Research Council of Italy (CNR) (Author)
  • Koushik Karmakar - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Andrey Maljuk - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Bernd Büchner - , Chair of Experimental Solid State Physics, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Vadim Grinenko - , Shanghai Jiao Tong University (Author)
  • Marina Putti - , University of Genoa, National Research Council of Italy (CNR) (Author)
  • Federico Caglieris - , National Research Council of Italy (CNR) (Author)

Abstract

The spontaneous Hall effect (SHE), a finite voltage occurring transversal to the electrical current in zero-magnetic field, has been observed in both conventional and unconventional superconductors, appearing as a peak near the superconducting transition temperature. The origin of SHE is strongly debated, with proposed explanations ranging from intrinsic and extrinsic mechanisms such as spontaneous symmetry breaking and time-reversal symmetry breaking (BTRS), Abrikosov vortex motion, or extrinsic factors like material inhomogeneities, such as non-uniform critical temperature (Tc) distributions or structural asymmetries. This work is an experimental study of the SHE in various superconducting materials. We focused on conventional, low-Tc, sharp transition Nb and unconventional, intermediate-Tc, smeared transition Fe(Se,Te). Our findings show distinct SHE peaks around the superconducting transition, with variations in height, sign and shape, indicating a possible common mechanism independent of the specific material. We propose that spatial inhomogeneities in the critical temperature, caused by local chemical composition variations, disorder, or other forms of electronic spatial inhomogeneities could explain the appearance of the SHE. This hypothesis is supported by comprehensive finite elements simulations of randomly distributed Tc’s by varying Tc-distribution, spatial scale of disorder and amplitude of the superconducting transition. The comparison between experimental results and simulations suggests a unified origin for the SHE in different superconductors, whereas different phenomenology can be explained in terms of amplitude of the transition temperature with respect to Tc-distribution.

Details

Original languageEnglish
Article number2546282
JournalScience and technology of advanced materials
Volume26
Issue number1
Early online dateAug 2025
Publication statusPublished - 2025
Peer-reviewedYes

External IDs

PubMed 40933231

Keywords

ASJC Scopus subject areas

Keywords

  • Inhomogeneities, simulations, spontaneous Hall effect, superconductors