https://doi.org/10.1140/epjb/s10051-021-00093-z
Regular Article - Solid State and Materials
Terahertz nonlinear optics of chiral semimetals RhSn, HfSn, and PdGa
1
MIIT Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, Institute of optoelectronics and Nanomaterials, Nanjing University of Science and Technology, 210094, Nanjing, People’s Republic of China
2
Discrete Event Simulation Research Team, RIKEN Center for Computational Science, 2-1 Hirosawa, 351-0198, Wako, Saitama, Japan
Received:
3
December
2020
Accepted:
31
March
2021
Published online:
3
May
2021
Topological semimetals have linear band dispersion around the band crossing which is near the Fermi level. Chiral topological semimetals have no spatial inversion symmetry, and they have non-vanishing second-order optical response. The band structure and nonlinear optical conductivity (NOC) 
of the isostructural chiral semimetals RhSn, HfSn, and PdGa are studied by the first-principles calculation in this work. Our calculation demonstrates that the maximal NOC of chiral semimetals RhSn is about 
under terahertz optical field with photon energy of 
12 meV, while the maximal NOCs of HfSn and PdGa are 
and 
, respectively. The relatively large NOC of RhSn can be interpreted by its multiple band crossing on the Fermi level, while multiple band crossings in the band structures of HfSn and PdGa are not on the Fermi level. Our calculations also reveal that the calculated imaginary part of dielectric function decreases with increasing photon energy, while the absorption coefficient increases with increasing photon energy in the terahertz region. The relatively large NOC makes chiral topological semimetal RhSn suitable for terahertz detection.
© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2021
