Seminars Archive

Stability, chemical structure, STM images, and Clar\'s aromatic sextets of graphene ribbons terminated with hydrogen, oxygen, ammonia, and water.

Abstract
We determine the stability, the geometry, STM images, the electronic, and magnetic structure of graphene-nanoribbon edges as a function of the hydrogen, oxygen, ammonia, and water content of the environment by means of density functional theory [1,2,3]. Antiferromagnetic zigzag ribbons are stable only at extremely low ultravacuum pressures. Under more standard conditions, the most stable structures are armchair edges and non-magnetic reconstructions of the zigzag edge. The stability, the STM images and the existence of exotic edge electronic states and/or magnetism is rationalized in terms of Clar\'s aromatic sextets. [1] T. Wassmann, A.P. Seitsonen, A.M. Saitta, M. Lazzeri, and F. Mauri, Phys. Rev. Lett. 101, 096402 (2008). [2] T. Wassmann, A.P. Seitsonen, A.M. Saitta, M. Lazzeri, and F. Mauri,J. Am. Chem. Soc. 132, 3440, (2010). [3] A.P. Seitsonen, A.M. Saitta, T. Wassmann, M. Lazzeri, and F. Mauri, Phys. Rev. B 82, 115425 (2010).