CMSP Section announced seminar on Monday

[Cond.Matt. & Stat.Mech.Section]

    INFORMAL SEMINAR on Chemical Physics



Monday, 18 May -    11:30 a.m. 

 

Luigi Stasi Seminar Room,  ICTP Leonardo Building (1st floor)

 

Prasenjit GHOSH    (Indian Institute of Science Education and Research, Pune)


"Tuning properties of supported graphene through chemical functionalization and substrate modifications"



Abstract


Graphene, a two dimensional monoatomic thick lattice of sp2 hybridized C atoms, has been a material of immense interest over the last few years because of its interesting properties. It is seen as a potential candidate for applications in diverse areas starting from electronics to catalysis. However, for most of the applications, graphene needs to be supported on substrates. As a result of the interaction between graphene and the substrate, properties of the graphene sheet might be altered. In my talk I will describe our efforts in understanding the interaction of graphene supported on ferromagnetic Ni(111) and Co(0001) substrates using first principles ab initio density functional theory based calculations. From our studies we find that, on these substrates, the Dirac cone is destroyed, there is a slight opening up of the band gap and an induced magnetic moment on the graphene sheet. The graphene sheet become ferrimagnetic. Further we show that by systematically hydrogenating the graphene sheet, it can be converted from ferri to ferromagnetic. Due to hydrogenation of the graphene sheet, the interaction of the the hydrogenated graphene sheet with the substrate is enhanced, resulting in charge transfer to the substrate, which in turn quenches the magnetic moment of the surface atoms drastically. We show that by intercalating an O layer between the hydrogenated graphene sheet and the substrate, one can alter the direction of charge flow resulting in increase of the magnetic moment of the surface Ni atoms by an order of magnitude.