Spin-dependent photogalvanic effect in the photodetector device based on penta-PtN2 monolayer

Abstract

As a nonlinear phenomenon, photogalvanic effect in low dimensional materials have attracted intensive attentions at recent years. In this paper, based on a typical two-dimensional pentagon material penta-PtN₂ monolayer, we built a photodetector device which including the vacancy and substitution-doping situations, and studied their spin photocurrents generated by the photogalvanic effect, respectively. It has been found that the spin photocurrents in these PtN₂-PhoDets exhibited the relations cos(2θ+θ₀) on the polarization angle, and different photon energies can affect these relations. Moreover, since the symmetry of PtN₂-PhoDets decrease from C_2v to C_s when introducing the vacancy and substitution-doping, the strength of spin photocurrents slightly enlarged showing the enhancement of PGE. Furthermore, there exhibited very high spin polarizations, which were close to the 100 % full spin polarization at the Pt-Vacancy, Doping(N)-Pt and Doping(Pt)-N2 situations, and then pure spin current can form at these special situations. Additionally, the relative high extinction ratios show that the PtN₂-PhoDets were high-sensitive. The findings indicated that the penta-PtN₂ monolayer was of considerable significances on the practical applications in low-energy power optoelectronic and spintronic devices.