Balint Nafradi
Ecole Polytechnique Fédérale de Lausanne, Switzerland
Title: Long, 140 ns electron spin lifetime in chemically synthesized graphene and related nanostructures and its strong interplay between the surface bound oxygen
Biography
Biography: Balint Nafradi
Abstract
The electron spin lifetime in an assembly of chemically synthesized graphene sheets was found to be extremely long at room temperature but also extremely sensitive to oxygen. Introducing small concentrations of physisorbed O2 onto the graphene surface reduced the exceptionally long 140 ns electron spin lifetime by an order of magnitude. This effect was completely reversible: removing the O2 by dynamic vacuum restored the spin lifetime. The presence of covalently bound oxygen also decreased the electron spin lifetime in graphene, although to a far lesser extent compared to physisorbed O2. The conduction electrons in graphene were found to play a significant role by counter-balancing the spin depolarization caused by oxygen molecules. Our results highlight the importance of chemical environment control and device packing in practical graphene based spintronic applications.
