Photogalvanic effect of two-dimensional magnetic NbSi<sub>2</sub>N<sub>4</sub>-WSi<sub>2</sub>N<sub>4</sub>-NbSi<sub>2</sub>N<sub>4</sub> heterojunction
摘要
We propose a photodetector based on a two-dimensional(2D) NbSi<sub>2</sub>N<sub>4</sub>-WSi<sub>2</sub>N<sub>4</sub>-NbSi<sub>2</sub>N<sub>4</sub> heterojunction, and investigate the transport properties of the photocurrent by using quantum transport simulations. The photogalvanic effect can be generated in this heterojunction due to noncentrosymmetric <i>C</i><sub>2v</sub> symmetry under the illumination of linearly polarized light within the visible range. A spin-polarized and polarization-sensitive photocurrent can be produced. The photocurrent is cosine-dependent (cos(2<i>θ</i>), cos(2<i>α</i>)) on polarization angle (<i>θ</i>) and incidence angle (<i>α</i>), respectively. A pure spin current and a perfect spin-filtering effect can be generated under both irradiation modes. Excellent spin-valve effect can be achieved during vertical irradiation. These results show that the two-dimensional magnetic NbSi<sub>2</sub>N<sub>4</sub>-WSi<sub>2</sub>N<sub>4</sub>-NbSi<sub>2</sub>N<sub>4</sub> heterojunction has application potential in low-energy consumption spintronics and low-dimensional photodetection.