Institute for Theoretical Solid State Physics and JARA, RWTH Aachen University, D-52074 Aachen, Germany.
Phys Rev Lett. 2013 May 24;110(21):216804. doi: 10.1103/PhysRevLett.110.216804.
We carry out an ab initio study of the structural, electronic, and magnetic properties of zigzag graphene nanoribbons on Cu(111), Ag(111), and Au(111). Both, H-free and H-terminated nanoribbons are considered revealing that the nanoribbons invariably possess edge states when deposited on these surfaces. In spite of this, they do not exhibit a significant magnetization at the edge, with the exception of H-terminated nanoribbons on Au(111), whose zero-temperature magnetic properties are comparable to those of free-standing nanoribbons. These results are explained by the different hybridization between the graphene 2p orbitals and those of the substrates and, for some models, also by the charge transfer between the surface and the nanoribbon. Interestingly, H-free nanoribbons on Au(111) and Ag(111) exhibit two main peaks in the local density of states around the Fermi energy, which originate from different states and, thus, do not indicate edge magnetism.
我们对在 Cu(111)、Ag(111)和 Au(111)表面上的锯齿型石墨烯纳米带的结构、电子和磁性进行了从头算研究。考虑了无氢和氢终止的纳米带，结果表明，当纳米带沉积在这些表面上时，它们始终具有边缘态。尽管如此，除了在 Au(111)上的氢终止纳米带之外，它们在边缘处没有表现出显著的磁化，而 Au(111)上的氢终止纳米带的零温磁性质与自由-standing 纳米带相当。这些结果可以通过石墨烯 2p 轨道和基底之间的不同杂化来解释，对于某些模型，也可以通过表面和纳米带之间的电荷转移来解释。有趣的是，在 Au(111)和 Ag(111)上的无氢纳米带在费米能级附近的局域态密度中表现出两个主要峰值，这源于不同的状态，因此并不表明边缘磁性。
