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Out-of-plane mirror symmetry-breaking provides a powerful tool for engineering the electronic property and the exciton behavior of two-dimensional materials. Here, combined the time-domain density functional theory with nonadiabatic dynamics, we...

The grain boundary (GB) composed of topological defects is likely to form where a merge occurred between two separate grains during the chemical vapor deposition fabrication process of in-planar two-dimensional heterostructural nanomaterials. Here, a systematic investigation regarding the geometrical stability, electronic, and magnetic properties of 3d transition metal (TM)-decorated in-planar graphene/hexagonal boron nitride bicrystalline heterostructure (GBN) was performed. The GGA + U approach is employed as the computation method. We selected a periodical grain boundary consisting of pentagon− heptagon or pentagon−octagon topological defects as the hybrid interface between graphene and h-BN domains, and we considered nine atoms, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu, for the TM addition. The GB was found to be the trapped region for all TM impurities during the adsorption process. The binding strength and charge transfer of adsorbed atoms were remarkably enhanced by the GB local topological defects. The adsorption of all nine TM atoms introduces a transformation from nonmagnetic states of pristine GBN to varying magnetization of TM−GBN. Spin-splitting band structures are found in all TM adsorption systems. Multiple electronic states can be achieved, including spin-polarized half-metallic states, half-semiconductor states, and metallic states. Both the charge injection from TM to GBN substrate and electron rearrangement between s, p, and d orbitals of impurity can work on the rich electronic and magnetic properties. Our findings indicate that it is feasible to obtain peculiar electronic and magnetic properties by surface TM addition, which can increase the utilization of in-planar graphene/h-BN heterostructure in spin-electronic materials and nanomagnet areas.

The lattice dislocation interacting with grain boundary in the polycrystal exerts an evident influence on the materials’ strength and toughness. A comprehensive study regarding the dislocation–twinning boundary (TB) interaction in α-titanium and TB migration is performed by employing molecular dynamic simulation. We analyze the interactions between dislocation and TB, under the conditions of plastic deformation and thermal stress, including the interaction between pure edge ⟨a⟩ dislocation and TB and the interaction between mixed type ⟨a⟩ dislocations and TB at 10 K/300 K. The ⟨c + a⟩ pyramidal transmitting slip mode is motivated in the case of edge dislocation– interaction at 300 K and then transforms into basal-dissociated dislocation after experiencing the complex dissociation and combination. The basal-dissociated pyramidal partial dislocation located in the second grain can be driven to penetrate through the second grain leaving the multiple stacking faults behind. Dissociation of incident basal dislocation on TB results in a nucleation of a twin embryo in twin crystals at room temperature. We determine the nature of the generated defects by means of the Burgers circuit analysis.