We have performed cascade genetic algorithm and ab initio atomistic thermodynamics under the framework of first-principles density functional theory to study the (meta-)stability of a wide range of LixNy clusters. We found that hybrid xc-functional i
s essential to address this problem as a local/semi-local functional simply fails even to predict a qualitative prediction. Most importantly, we find that though in bulk Lithium Nitride, Li rich phase, i.e. Li3N, is the stable stoichiometry, in small LixNy clusters N-rich phases are more stable at thermodynamic equilibrium. We further show a that these N-rich clusters are promising hydrogen storage material because of their easy adsorption and desorption ability at respectively low (< 300K) and moderately high temperature (> 600K).
We have carried out first-principles based DFT calculation on electronic properties of silicene monolayer on various (111) semi-conducting surfaces. We find that the relative stability and other properties of the silicene overlayer depends sensitivel
y on whether the interacting top layer of the substrate is metal or non-metal terminated. The nature of silicene-monolayer on the metal termi- nated surface can be metallic or even magnetic, depending upon the choice of the substrate. The silicene overlayer undergoes n-type doping on metal terminated surface while it undergoes p-type doping on non metal terminated surfaces of the semiconductor substrates.
After the work of Rindler and Ishak, it is now well established that the bending of light is influenced by the cosmological constant {Lambda} appearing in the Schwarzschild-de Sitter spacetime. We show that their method, when applied to the galactic
halo gravity parametrized by a constant {gamma}, yields exactly the same {gamma}- correction to Schwarzschild bending as obtained by standard methods. Different cases are analyzed, which include some corrections to the special cases considered in the original paper by Rindler and Ishak.
