Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain.
Institut für Chemie und Biochemie, Freie Universität Berlin , Takustr. 3, 14195 Berlin, Germany.
Nano Lett. 2017 Nov 8;17(11):6991-6996. doi: 10.1021/acs.nanolett.7b03553. Epub 2017 Oct 5.
Chemically doped graphene could support plasmon excitations up to telecommunication or even visible frequencies. Apart from that, the presence of dopant may influence electron scattering mechanisms in graphene and thus impact the plasmon decay rate. Here I study from first principles these effects in single-layer and bilayer graphene doped with various alkali and alkaline earth metals. I find new dopant-activated damping channels: loss due to out-of-plane graphene and in-plane dopant vibrations, and electron transitions between graphene and dopant states. The latter excitations interact with the graphene plasmon, and together they form a new hybrid mode. The study points out a strong dependence of these features on the type of dopants and the number of layers, which could be used as a tuning mechanism in future graphene-based plasmonic devices.
化学掺杂的石墨烯可以支持等离子体激元激发，直至电信甚至可见光频率。除此之外，掺杂剂的存在可能会影响石墨烯中的电子散射机制，从而影响等离子体衰减率。在这里，我从第一性原理研究了单层和双层石墨烯中掺杂各种碱金属和碱土金属的这些效应。我发现了新的掺杂剂激活的阻尼通道：由于石墨烯平面外和平面内掺杂剂振动以及石墨烯和掺杂剂态之间的电子跃迁引起的损耗。后一种激发与石墨烯等离子体相互作用，它们共同形成一种新的混合模式。研究指出，这些特性强烈依赖于掺杂剂的类型和层数，这可以用作未来基于石墨烯的等离子体器件中的调谐机制。
