Yb4As3 and Yb4(As0.71Sb0.29)3, two ways to heavy-fermion character

R. Pittini, M. Ikezawa, A. Ochiai, H. Aoki, T. Suzuki

Research output: Contribution to journalArticlepeer-review


After the observation of heavy-fermion characteristics in the charge-ordered phase of Yb4As3, it is surprising that Yb4(As0.71Sb0.29)3 shows heavy-fermion behavior, though the charge ordering is suppressed. To shed more light onto this enigma, we measured the optical reflectivity of Yb4(As0.71Sb0.29)3 at several temperatures down to 15 K in the photon energy range from 1 meV to 5.5 eV. The comparison of the optical functions of Yb4As3 and Yb4(As0.71Sb0.29)3 revealed decisive differences in the far-IR region. For the latter material, we found an hybridization gap of 3.3 meV, absent in Yb4As3. The effective mass of the conduction carriers takes the temperature-independent value of 2 me in Yb4As3, while m* shows a logarithmic temperature dependency and reaches 80 me at 15 K in Yb4(As0.71Sb0.29)3. This proves that two different mechanisms lead to a large y value in Yb4As3 and Yb4(As0.71Sb0.29)3.

Original languageEnglish
Pages (from-to)345-346
Number of pages2
JournalJournal of Magnetism and Magnetic Materials
Issue numberPART 1
Publication statusPublished - 1998 Jan
Externally publishedYes


  • Electronic phase transitions
  • Heavy fermions
  • Optical spectroscopy
  • Rare-earth pnictides

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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