A detailed low-energy electronic structure of a Kondo insulator YbB12 was revealed by a synergetic combination of ultra-high-resolution laser photoemission spectroscopy (PES) and time-resolved PES. The former confirmed a 25-meV pseudogap corresponding to the Kondo temperature of this material, and more importantly, it revealed that a 15-meV gap and a Kondo-peak feature developed below a crossover temperature of T∗∼110K. In harmony with this, the latter discovered a very long recombination time exceeding 100 ps below ∼T∗. This is a clear manifestation of photoexcited carriers due to the bottleneck in the recovery dynamics, which is interpreted as a developing hybridization gap of a hard gap.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2015 Oct 12|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics