First principle calculations of thermodynamic properties of pure graphene sheet and graphene sheets with Si, Ge, Fe, and Co impurities

Abstract

The thermal properties of pure graphene and graphene-impurity (impurity = Fe, Co, Si, and Ge) sheets have been investigated at various pressures (0-7 GPa) and temperatures (0-900 K). Some basic thermodynamic quantities such as bulk modulus, coefficient of volume thermal expansion, heat capacities at constant pressure and constant volume of these sheets as a function of temperature and pressure are discussed. Furthermore, the effect of the impurity density and tensile strain on the thermodynamic properties of these sheets are investigated. All of these calculations are performed based on the density functional theory and full quasi harmonic approximation.

Strain-modulated ultrafast magneto-optic dynamics of graphene nanoflakes decorated with transition-metal atoms*

“…A substantial amount of theoretical and experimental works have predicted that adsorption of transition metal atoms on graphene can effectively induce and tune band gaps of GNFs. [19][20][21][22][23] It is worth noting that the transition metal atoms (TM-atoms) doped graphene structures have been synthesized experimentally with satisfactory stabilities. [24][25][26][27] Previous studies have, without exception, expounded that doped TM-atoms can also significantly manipulate the electronic and magnetic properties of graphene.…”

One-dimensional method of investigating the localized states in armchair graphene-like nanoribbons with defects

“…For example, the ballistic thermoelectric properties for the bended GNRs and the graphene with impurities have been investigated by the first-principles calculations and the quantum transport theory. [17,18] For aGNR, the TB calculation results show that they may be conductors or semiconductors. [7,19] The first-principles results show that for the metal-type aGNR in the TB model, in fact, there is still a very small gap.…”