6533b7ddfe1ef96bd1275415
RESEARCH PRODUCT
Robust hybridization gap in a Kondo Insulator YbB${}_{12}$ probed by femtosecond optical spectroscopy
A. R. PokharelS. Y. AgustssonV. V. KabanovF. IgaToshiro TakabatakeH. OkamuraJ. Demsarsubject
Condensed Matter - Strongly Correlated ElectronsCondensed Matter - Materials ScienceStrongly Correlated Electrons (cond-mat.str-el)Materials Science (cond-mat.mtrl-sci)FOS: Physical sciencesdescription
In heavy fermions the relaxation dynamics of photoexcited carriers has been found to be governed by the low energy indirect gap, E$_{g}$, resulting from hybridization between localized moments and conduction band electrons. Here, carrier relaxation dynamics in a prototype Kondo insulator YbB${}_{12}$ is studied over large range of temperatures and over three orders of magnitude. We utilize the intrinsic non-linearity of dynamics to quantitatively determine microscopic parameters, such as electron-hole recombination rate. The extracted value reveals that hybridization is accompanied by a strong charge transfer from localized 4f-levels. The results imply the presence of a hybridization gap up to temperatures of the order of E$_{g}$/k$_{B}\approx200$ K, which is extremely robust against electronic excitation. Finally, below 20 K the data reveal changes in the low energy electronic structure, attributed to short-range antiferromagnetic correlations between the localized levels.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2021-03-04 |