Comprehensive anisotropic linear optical properties of the Weyl semimetals TaAs and NbAs

Zu，Rui1; Gu，Mingqiang2; Min，Lujin1; Hu，Chaowei3; Ni，Ni3; Mao，Zhiqiang4; Rondinelli，James M.5; Gopalan，Venkatraman1,4,6

2021-04-26

10.1103/PhysRevB.103.165137

Physical Review B   影响因子和分区

2469-9950

2469-9969

TaAs and NbAs are two of the earliest identified Weyl semimetals that possess many intriguing optical properties, such as chirality-dependent optical excitations and giant second harmonic generation (SHG). Linear and nonlinear optics have been employed as tools to probe the Weyl physics in these crystals. Here, we extend these studies to address two important aspects: determining the complete anisotropic dielectric response and exploring if and how they can reveal essential Weyl physics. We determine the complete anisotropic dielectric functions of TaAs and NbAs by combining spectroscopic ellipsometry and density functional theory (DFT). Parameterized Lorentz oscillators are reported from 1.2-6 eV (experiment) and 0-6 eV (DFT), and good agreement is shown between them. Both linear and nonlinear optical properties have been previously reported to reveal Weyl physics. We suggest that strong optical resonances from trivial bands are the likely origin of the large optical SHG previously reported at these energies. Furthermore, by comparing the contribution of a small k-space centered around the Weyl cones with the total linear dielectric function, we find that these contributions are highly anisotropic and are <25% of the total dielectric function below0.5eV; above1eV, these contributions are negligible. Thus, the study of Weyl physics using optical techniques requires very low energies, and even there, a careful assessment is required in distinguishing the much smaller contributions of the Weyl bands from the dominant contributions of the trivial bands and Drude response to the total dielectric function.

SCI ; EI

英语

其他

WOS:000647174300002

20211910336737

Anisotropy ; Density functional theory ; Harmonic generation ; Niobium compounds ; Optical properties ; Spectroscopic ellipsometry ; Tantalum compounds

Light/Optics:741.1 ; Nonlinear Optics:741.1.1 ; Classical Physics; Quantum Theory; Relativity:931 ; Optical Variables Measurements:941.4

PHYSICS

2-s2.0-85105439774

Scopus

1.Department of Materials Science and Engineering,Pennsylvania State University,University Park,16802,United States
2.Shenzhen Institute for Quantum Science and Engineering (SIQSE),Department of Physics,Southern University of Science and Technology,Shenzhen,518055,China
3.Department of Physics and Astronomy,California NanoSystems Institute,University of California,Los Angeles,90095,United States
4.Department of Physics,Pennsylvania State University,University Park,16802,United States
5.Department of Materials Science and Engineering,Northwestern University,Evanston,60208,United States
6.Department of Engineering Science and Mechanics,Pennsylvania State University,University Park,16802,United States

Zu，Rui,Gu，Mingqiang,Min，Lujin,et al. Comprehensive anisotropic linear optical properties of the Weyl semimetals TaAs and NbAs[J]. Physical Review B,2021,103(16).

Zu，Rui.,Gu，Mingqiang.,Min，Lujin.,Hu，Chaowei.,Ni，Ni.,...&Gopalan，Venkatraman.(2021).Comprehensive anisotropic linear optical properties of the Weyl semimetals TaAs and NbAs.Physical Review B,103(16).

Zu，Rui,et al."Comprehensive anisotropic linear optical properties of the Weyl semimetals TaAs and NbAs".Physical Review B 103.16(2021).