Localized-to-itinerant transition preceding antiferromagnetic quantum critical point and gapless superconductivity in CeRh0.5Ir0.5In5

Shinji Kawasaki, Toshihide Oka, Akira Sorime, Yuji Kogame, Kazuhiro Uemoto, Kazuaki Matano, Jing Guo, Shu Cai, Liling Sun, John L. Sarrao, Joe D. Thompson, Guo qing Zheng

Research output: Contribution to journalArticlepeer-review

Abstract

A fundamental problem posed from the study of correlated electron compounds, of which heavy-fermion systems are prototypes, is the need to understand the physics of states near a quantum critical point (QCP). At a QCP, magnetic order is suppressed continuously to zero temperature and unconventional superconductivity often appears. Here, we report pressure (P)-dependent 115In nuclear quadrupole resonance (NQR) measurements on heavy-fermion antiferromagnet CeRh0.5Ir0.5In5. These experiments reveal an antiferromagnetic (AF) QCP at PcAF=1.2 GPa where a dome of superconductivity reaches a maximum transition temperature Tc. Preceding PcAF, however, the NQR frequency νQ undergoes an abrupt increase at Pc* = 0.8 GPa in the zero-temperature limit, indicating a change from localized to itinerant character of cerium’s f-electron and associated small-to-large change in the Fermi surface. At PcAF where Tc is optimized, there is an unusually large fraction of gapless excitations well below Tc that implicates spin-singlet, odd-frequency pairing symmetry.

Original languageEnglish
Article number148
JournalCommunications Physics
Volume3
Issue number1
DOIs
Publication statusPublished - Dec 1 2020

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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