Open AccessUltrafast quasiparticle dynamics and coherent phonon in nodal line topological material LaBi
Author(s) -
Yu Bao,
Zhen Tian,
Fei Sun,
Darren C. Peets,
Xinbo Bai,
D. L. Feng,
Jimin Zhao
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.383995
Subject(s) - ultrashort pulse , phonon , quasiparticle , topological insulator , laser , physics , fluence , laser linewidth , spectroscopy , optics , terahertz radiation , condensed matter physics , quantum mechanics , superconductivity
We use an ultrafast optical pump-probe spectroscopy to study quasiparticle (QP) dynamics in a topological insulator LaBi. Temperature-dependent optical measurements have been carried out, by which we observed nearly constant fast component (with a lifetime of 0.15 ps) and slow component (with a lifetime of 1.5 ps) for the whole range from 10 K to 295 K. The laser fluence dependence result shows that there is no saturation for the QP dynamics up to 3.3 mJ /cm 2 . Moreover, an Eg mode transverse optical (TO) coherent phonon has also been observed, with a frequency of 2.8 THz. Our results provide for the first time the ultrafast dynamics information of both the QPs and coherent phonons in a nodal line topological material.