Circular Photocurrent in Weyl Semimetals with Mirror Symmetry
- Ioffe Physical–Technical Institute, Russian Academy of Sciences (Russian Federation)
We have considered theoretically Weyl’s semimetals, for which the point symmetry group contains reflection planes and which have equivalent valleys with opposite chiralities. These materials include the most often studied compounds, viz., monopnictides TaAs, NbAs, TaP, NbP of transition metals, as well as Bi{sub 1 ‒} {sub x}Sb{sub x} alloys. Circular photogalvanic current inverting its direction upon the sign reversal of the circular polarization has been calculated for light absorption under direct optical transitions near Weyl points. The total contribution of all valleys to the photocurrent differs from zero beyond the limits of Weyl’s model when the spin-independent tilt linear in wavevector k or spin-dependent terms cubic in k are taken into account additionally in the effective electron Hamiltonian. When the tilt of the energy dispersion curve in a Weyl semimetal of symmetry C{sub 4v} is considered, the photogalvanic current can be expressed in terms of the components of rank-two symmetric tensor determining the energy spectrum of carriers near a Weyl’s node. At low temperatures, this contribution to the photocurrent is excited in a certain limited frequency interval Δ. The photocurrent associated with cubic corrections in the optical absorption region is proportional to the square of light frequency and is generated both within window Δ and beyond its limits.
- OSTI ID:
- 22917706
- Journal Information:
- Journal of Experimental and Theoretical Physics, Vol. 129, Issue 1; Other Information: Copyright (c) 2019 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
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