Samarium doped zinc-magnesium-phosphate glasses having composition (60 – x)P2O5–10MgO–30ZnO– xSm2O3 where x= 0.1, 0.3, 0.6, 1.0 mol % were prepared by melt quenching technique. Archimedes method was...

Using the first-principles procedure of density-functional-theory within tight-binding approximation and nonequilibrium Green's function formalism, this paper reports on the impact of vacancy defects on the structural, electronic and transport properties of hydrogen-passivated graphene atomic sheet. After the introduction of vacancy defects in graphene atomic sheet passivated with hydrogen atoms, apart from increase in band gap, a suppression is noted in the intensity of transmission channels and density of states arising from the long array deformations of the graphene sheet and a corresponding shift of the Fermi level. This in turn decreases the conductance of the defected graphene atomic sheet. In case of slow-ion bombardment method, the conductance of the sheet decreases slowly and its value of the order 10-6 S before vanishing the percolation drops to the order 10-10 as the percolation of the sheet is destroyed. But in case of fast bombardment the conductance of the sheet shows some linear drop before vanishing of the percolation of the sheet and its value of the order 10-6 S before vanishing the percolation drops to the order 10-10 as the percolation of the sheet is destroyed. Furthermore, it is found that the atomic vacancy defects effectively terminate the original smooth sp2-hybrid network of 2D graphene atomic sheet that leads to modify its electronic and transport properties, especially decreases its electrical conductance. Interestingly, transmission spectrum of graphene atomic wire with large vacancy defects of 143 is similar to that of a molecular benzene ring.