1998/09/15 by H. Okamura, S. Kimura, Shin‐ichi Kimura +7 · 1 citation
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Diamond and Carbon-based Materials Research #High-pressure geophysics and materials #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.58.r7496
published as Phys. Rev. B58, R7496 (1998) · 4 pages, 4 figures
openalex publication_date 1998/09/15 · arxiv created 1998/10/13 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Optical reflectivity experiments have been conducted on single crystals of the Kondo insulator YbB12 in order to obtain its optical conductivity, \ensuremathσ(\ensuremathω). Upon cooling below 70 K, a strong suppression of \ensuremathσ(\ensuremathω) is seen in the far-infrared region, indicating the opening of an energy gap of \ensuremath∼25meV. This gap development is coincident with a rapid decrease in the magnetic susceptibility, which shows that the gap opening has significant influence on magnetic properties. A narrow, asymmetric peak is observed at \ensuremath∼40meV in \ensuremathσ(\ensuremathω), which is attributed to optical transitions between the Yb 4f-derived states across the gap. In addition, a broad peak is observed at \ensuremath∼0.25eV. This peak is attributed to transitions between Yb 4f-derived states and the p\ensuremath-d band, and is reminiscent of similar peaks previously observed for rare-earth hexaborides.