Investigation of electronic, dynamic and mechanic properties of arsenene-silicon compound : First principles study[پايان نامه فارسي]

Nayereh Alyasin

Two-dimensional materials emerged as materials with notable and distinguishing properties and potential applications in various fields. The atomically thin and single-layer structure of these materials creates exceptional electronic, optical, mechanical, and thermal properties that differ from their three-dimensional counterparts. One of the important known materials in this field is graphene. However, its zero band gap limited the use of this material and encouraged scientists to identify other 2D materials. In the meantime, arsenene is being noticed because of its special characteristics and since simulating compound with other materials also causes modification, in this work, the properties of monolayer puckered arsenene in its pristine state and while it is combined by silicon in the fourth groups of the periodic table are investigated. At first, its lattice structures are analyzed and by comparing the obtained values, it is shown that monolayer arsenenesilicon from one direction is stretched by 0.35 Å. Its electronic properties of monolayer puckered arsenene shows an indirect band gap with approximately 0.77 eV as long as the PBE exchange-correlation and AsSi is then studied and demonstrating that the Dirac point appears in the electronic band structure for AsSi, and the contribution of the valence shell of arsenene and silicon at close to and far from Fermi energies is considered and it is found that orbital Pz in both arsenene and silicon has the most contribution . Its dynamical properties are next studied. In this section, y not observing any imaginary branch in the phonon dispersion relation diagram, we concluded the stability of the material. the velocity sound near the 􀀀 point is also evaluated and the contribution of each atom at various energies was then determined.finally, its mechanical properties are calculated and discussed for pristine monolayer puckered arsenene and arsenene-silicon of that one. In comparison to its pure condition, we discovered that Young’s modulus in AsSi has reduced. This indicates that our material has grown more flexible and exhibits more resistance to external forces.Importantly, AsSi has a negative Poisson ratio, distinguishing it apart from other materials and it is considered a valuable distinction for this material. Keywords— DFT, arsenene-silicon, Puckered structure, Dirac point, mechanical properties and Negative Poisson’s ratio