Raman spectra of monolayer arsenene with external strain are determined with density functional theory. Due to lower structural symmetry, deformation induced by external strain regulates Raman mode splitting and leads to Raman mode shifts as well. Our calculations suggest that the structural deformation induced by external strain can be clearly identified by Raman scattering.

In the PIC method of particle simulations,the physical variables related to the fields are assigned to the grids,while the particles can be anywhere in the simulation domain.Using this method,we design a 2D particle simulation code,and numerically study two common physical phenomena in space physics:beam instability and magnetic reconnection.In the beam instability,the beam plasma streams in the background plasma with the velocity V_b=10V_-A(V_-A is Alfvén speed),and the Alfvén waves are excited through wave-particle interactions.In the magnetic reconnection,the Harris current sheet can induce the magnetic reconnection,and the B_-y shows quadrupolar structure.