Adsorption of monovalent metal atoms on graphene: a theoretical approach

Abstract

This work investigates, using first-principles calculations, electronic and structural properties of hydrogen, lithium, sodium, potassium and rubidium that are adsorbed, in a regular pattern, on a graphene surface. The results for H-graphene (graphane) and Li-graphene were compared with previous calculations. The present results do not support previous claims that the Li-C bond in such a layer would result in an sp(2) to an sp(3) transition of carbon orbitals, being more compatible with some ionic character for the covalent bond and with lithium acting as an electron acceptor in a bridging environment. Calculations were also performed for the Na, K, and Rb-graphene systems, resulting in a similar electronic behaviour but with a more pronounced ionic character than for Li-graphene. Energy calculations indicate the possible stability of such ad-graphene layers, with only the Li-graphene being possible to be spontaneously obtained.

First-principles study of the interaction of hydrogen molecular on Na-adsorbed graphene

“…This signifies that Na-adsorbed graphene in 2 Â 2 supercell is less stable than its constituent systems (the pristine graphene and isolated Na atom), which agrees with the previously reported results for two-atom unit cell (Medeiros et al 2010).…”

“…The shifting of Dirac point below the Fermi-level has also been discussed in Mukherjee and Kaloni (2012) for nitrogen-doped (N-doped) graphene system, where N contributes as an electron donor as similar to Na in the present work. Figure 4 also indicates its modified conductivity with reference to zero-band gap pristine graphene, which is consistent with the Medeiros et al (2010). The breaking of symmetry, on the other hand, introduces the magnetic behavior.…”

“…Graphene, its derivatives and other similar two-dimensional compounds have become frontier area of research activities, and also the materials of commercial interest in recent days (Medeiros et al 2010;Johll et al 2009;Thapa et al 2011;Chan et al 2008;Karki and Adhikari 2014;Ci et al 2010;Kaloni et al 2011;Park and Louie 2010;Esquinazi et al 2003;Mukherjee and Kaloni 2012;Ugeda et al 2010;Singh et al 2013;Kaloni et al 2014;Saha et al 2009;Kaloni et al 2012;Wu and Yang 2012;Dai et al 2009;Choi and Jhi 2009). Graphene, hexagonal boron nitride (h-BN) and their doped structures have been studied by a number of research groups to see their potential applications in advanced electronics and optics (Ci et al 2010;Mukherjee and Kaloni 2012;Singh et al 2013).…”

“…The varying band gaps of these new materials and other carbon nanostructures include extensively a wide range of conductivity with all the potential applications in semiconductor (Mukherjee and Kaloni 2012;Kaloni et al 2014), conductor (Ataca et al 2008) to superconductor (Ugeda et al 2010). The easily tunable structural stability, band structure and other electronic/magnetic properties, and also photonic and vibrational properties of graphene have been achieved through a number of techniques like: via vacancies Ugeda et al 2010;Singh et al 2013;Kaloni et al 2012), atomic/molecular doping (Medeiros et al 2010;Johll et al 2009;Thapa et al 2011;Chan et al 2008;Karki and Adhikari 2014;Saha et al 2009;Wu and Yang 2012), functionalization (Wood et al 2012;Ulman et al 2014), irradiation (Esquinazi et al 2003) and external fields (Park and Louie 2010). The modified compounds carry potential applications over many dimensions like in electronics (Geim 2009;Novoselov et al 2005Novoselov et al , 2007, spintronics (Palacios et al 2008;Ding et al 2011), chemical sensors (Saha et al 2009), and energy storage (Pumera 2011).…”

“…The adsorption of alkali metal atoms on graphitic materials has been widely studied to see the interaction between them (Medeiros et al 2010;Liu et al 2011). Being as electron donor atoms, electronic charge transfers from adsorbed alkali atoms (Li, Na and K) to graphene, which causes change in band structure and neutrality of the new materials (Mukherjee and Kaloni 2012).…”