Transition Metal Adatoms on Graphyne: Electronic Structure and Thermoelectric Properties*

Thermoelectricity is the advantageous property of some materials to convert waste thermal energy into electricity. The research interest of achieving high thermoelectric efficiency increased in the recent years, specially promoted by the demand for eco-friendly energy harvesting technology. It is known that 2D systems provide much higher thermoelectric conversion than bulk materials, due to enhancement of Seebeck coefficient and reduction of phonon thermal conductivity. Therefore, graphene nanostructures and other 2D sp-sp2 carbon allotropes such as graphynes and graphdiynes are promising candidates to thermoelectric applications and spin caloritronics, an emerging technology combining spintronics and thermoelectronics.
Here we investigated structural and electronic properties of Mn and Fe adatoms adsorbed on Graphyne (Gy) using density functional theory. We verified that the band structure of Gy sheets, strongly depends on the adatom distance to the plane. To explore the effects of quantum confinement, we also discuss the functionalization of Gy nanoribbons. Finally, we focus on the electronic transport and thermoelectric quantities with the perspective of spin caloritronics nanodevices.