First Principle Study On The Stability?Electronic Structure And Related Properties Of Several New Nanomaterials

In recent years,two-dimensional?2D?nanomaterials represented by graphene set off a wave of research in many fields such as nanoelectronics and materials science.The novel 2D nanomaterials with unique geometries have rich electronic,optical,magnetic and magnetic properties.Recently,the 2D nanostructures composed of Group V and 13-15 elements also attract much attention.This paper first introduces the development of nanomaterials,especially 2D nanomaterials,and then introduces the research methods and theories.In the third to the fifth chapters,based on the first-principles calculations,three types of low-dimensional nanostructures are studied:Pmma-CO has a 2.4 eV direct bandgap and the direct band gap characteristics can be retained up to 12%stress.It possesses energetic,kinetic,thermodynamic and mechanical stability.Moreover,Pmma-CO shows excellent mechanical strength(in-plane stiffness up to 475.7 Nm^-1).Once synthesized,the Pmma-CO monolayer is expected to enhance the mechanical properties of the nanocomposite.A tetragonal?t-?AlP monolayer with a 1.56 eV direct band-gap was designed.Not only the stability and properties of t-AlP but also the effect of stress and substrate on electronic properties were studied.Under relatively small biaxial stress,t-AlP can occur direct-indirect bandgap and semiconducting-metal transitions.In addition,the hydrogen storage properties of low-dimensional B₃₆ sheets modified with alkali metal Na were studied.The B₃₆-2Na system has a hydrogen storage capacity of 4.4 wt%and a moderate adsorption energy of 0.25 eV/H₂.Alkali metal modified low-dimensional boron clusters are potential materials for hydrogen storage.