Perfect spin filter and strong current polarization in carbon atomic chain with asymmetrical connecting points

The spin-dependent electron transport properties through a single-carbon atomic chain (SCAC) sandwiched between two-zigzag-graphene-nanoribbon (zGNR) electrodes are investigated by performing first-principles calculations based on the nonequilibrium Green's function (NEGF) approach in combination with spin density functional theory (DFT). Our calculations show that SCAC connecting two zGNRs with asymmetry-contacting points is a perfect spin filter in the transmission function within a large energy range. Moreover, the spin-dependent electron transmission spectra exhibit robust transport polarization characteristics and a strong current polarization behavior (almost 100%) can be found. The microscopic mechanisms are proposed for the spin-related phenomena

GaN/surface-modified graphitic carbon nitride heterojunction : promising photocatalytic hydrogen evolution materials

The coupling of two-dimensional (2D) layered materials is an effective way to realize photocatalytic hydrogen production. Herein, using first-principles calculations, the photocatalytic properties of GaN/CNs heterojunctions formed by two different graphite-like carbon nitride materials and GaN monolayer are discussed in detail. The results show that the GaN/C2N heterojunction can promote the effective separation of photogenerated electron and hole pairs, which is attributed to its type-II band orientation and high carrier mobility. However, the low overpotential of GaN/C2N for photocatalytic hydrogen production limits the photocatalytic performance. On this basis, we adjust the CBM position of the GaN/C2N heterojunction by applying an electric field to enhance its hydrogen evolution capability. In addition, the GaN/g-C3N4 is a type-I heterojunction, which is suitable for the field of optoelectronic devices. This work broadens the field of vision for the preparation of highly efficient photocatalysts