Charge-neutral fermions and magnetic field-driven instability in insulating YbIr3Si7

Y. Sato, S. Suetsugu, T. Tominaga, Y. Kasahara, S. Kasahara, T. Kobayashi, Shunsaku Kitagawa, K. Ishida, R. Peters, T. Shibauchi, A. H. Nevidomskyy, L. Qian, E. Morosan, Y. Matsuda

Research output: Contribution to journalArticlepeer-review

Abstract

Kondo lattice materials, where localized magnetic moments couple to itinerant electrons, provide a very rich backdrop for strong electron correlations. They are known to realize many exotic phenomena, with a dramatic example being recent observations of quantum oscillations and metallic thermal conduction in insulators, implying the emergence of enigmatic charge-neutral fermions. Here, we show that thermal conductivity and specific heat measurements in insulating YbIr3Si7 reveal emergent neutral excitations, whose properties are sensitively changed by a field-driven transition between two antiferromagnetic phases. In the low-field phase, a significant violation of the Wiedemann-Franz law demonstrates that YbIr3Si7 is a charge insulator but a thermal metal. In the high-field phase, thermal conductivity exhibits a sharp drop below 300 mK, indicating a transition from a thermal metal into an insulator/semimetal driven by the magnetic transition. These results suggest that spin degrees of freedom directly couple to the neutral fermions, whose emergent Fermi surface undergoes a field-driven instability at low temperatures.

Original languageEnglish
Article number394
JournalNature communications
Volume13
Issue number1
DOIs
Publication statusPublished - Dec 2022

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Fingerprint

Dive into the research topics of 'Charge-neutral fermions and magnetic field-driven instability in insulating YbIr3Si7'. Together they form a unique fingerprint.

Cite this