Circular photocurrent in Weyl semimetals with mirror symmetry

Abstract

We have studied theoretically the Weyl semimetals the point symmetry group of which has reflection planes and which contain equivalent valleys with opposite chiralities. These include the most frequently studied compounds, namely the transition metals monopnictides TaAs, NbAs, TaP, NbP, and also Bi${}_{1-x}$Sb${}_x$ alloys. The circular photogalvanic current, which inverts its direction under reversal of the light circular polarization, has been calculated for the light absorption under direct optical transitions near the Weyl points. In the studied materials, the total contribution of all the valleys to the photocurrent is nonzero only beyond the simple Weyl model, namely, if the effective electron Hamiltonian is extended to contain either an anisotropic spin-dependent linear contribution together with a spin-independent tilt or a spin-dependent contribution cubic in the electron wave vector $\mathbf{k}$. With allowance for the tilt of the energy dispersion cone in a Weyl semimetal of the $C_{4v}$ symmetry, the photogalvanic current is expressed in terms of the components of the second-rank symmetric tensor that determines the energy spectrum of the carriers near the Weyl node; at low temperature, this contribution to the photocurrent is generated within a certain limited frequency range $\Delta$. The photocurrent due to the cubic corrections, in the optical absorption region, is proportional to the light frequency squared and generated both inside and outside the $\Delta$ window.

arXiv comment8 pages, 2 figures, JETP in press

References in corpus (13)

• Weyl and Dirac Semimetals in Three Dimensional Solids
• Type-II Weyl Semimetals
• Observation of Weyl nodes in TaAs
• Quantized circular photogalvanic effect in Weyl semimetals
• Direct optical detection of Weyl fermion chirality in a topological semimetal
• Photocurrents in Weyl semimetals
• Topological surface states and Fermi arcs of the noncentrosymmetric Weyl semimetals TaAs, TaP, NbAs, and NbP
• A new topological semimetal with iso-energetic Weyl fermions in TaAs under high pressure
• Circular and magnetoinduced photocurrents in Weyl semimetals
• An Anomalous Circular Photogalvanic Effect in the Weyl Semimetal TaAs
• Photocurrents in gyrotropic Weyl semimetals
• Topological Weyl semimetals in $\mathrm{Bi}$${}_{1-x}$$\mathrm{Sb}$${}_x$ alloys
• Combinatorics in tensor integral reduction

Cited by in corpus (4)

• Difference frequency generation in topological semimetals
• Semiclassical theory of the circular photogalvanic effect in gyrotropic systems
• Nonperturbative Topological Current in Weyl and Dirac Semimetals in Laser Fields
• Nonlinear Absorption and Photocurrent in Weyl Semimetals