Fermi velocity engineering in graphene by substrate modification
Fermi velocity engineering in graphene by substrate modification
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DOI：
10.1038/srep00590
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发表时间：
2012-08-20
影响因子：
4.6
通讯作者：
Lanzara, Alessandra
中科院分区：
文献类型：
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作者：
Hwang, Choongyu;Siegel, David A.;Lanzara, Alessandra
费米速度v(F)是材料研究中的关键概念之一，因为它承载着关于各种基本性质的信息。随着设备应用需求的增加，石墨烯被视为工程应用的原型系统。事实上，通过改变载流子浓度n来改变v(F)的方法已经取得了成功。在这里，我们提出了一种在保持n不变的情况下设计v(F)的有效而简单的新方法。我们发现，当石墨烯的嵌入环境被改变时，石墨烯的v(F)与其介电常数成反比，v(F)接近于2.5×10(6)m/S，这是迄今为止所研究的衬底上石墨烯的最高值，并且(Ii)明显区别于普通的费米液体。这种方法为在包括拓扑绝缘体在内的各种二维电子系统中实现费米速度工程提供了一条新的途径。
The Fermi velocity, v(F), is one of the key concepts in the study of a material, as it bears information on a variety of fundamental properties. Upon increasing demand on the device applications, graphene is viewed as a prototypical system for engineering v(F). Indeed, several efforts have succeeded in modifying v(F) by varying charge carrier concentration, n. Here we present a powerful but simple new way to engineer v(F) while holding n constant. We find that when the environment embedding graphene is modified, the v(F) of graphene is (i) inversely proportional to its dielectric constant, reaching v(F) similar to 2.5 x 10(6) m/s, the highest value for graphene on any substrate studied so far and (ii) clearly distinguished from an ordinary Fermi liquid. The method demonstrated here provides a new route toward Fermi velocity engineering in a variety of two-dimensional electron systems including topological insulators.