Nair R R, Blake P, Grigorenko A N, Novoselov K S, Booth T J, Stauber T, Peres N M R, Geim A K
Manchester Centre for Mesoscience and Nanotechnology, University of Manchester, M13 9PL Manchester, UK.
Science. 2008 Jun 6;320(5881):1308. doi: 10.1126/science.1156965. Epub 2008 Apr 3.
There are few phenomena in condensed matter physics that are defined only by the fundamental constants and do not depend on material parameters. Examples are the resistivity quantum, h/e2 (h is Planck's constant and e the electron charge), that appears in a variety of transport experiments and the magnetic flux quantum, h/e, playing an important role in the physics of superconductivity. By and large, sophisticated facilities and special measurement conditions are required to observe any of these phenomena. We show that the opacity of suspended graphene is defined solely by the fine structure constant, a = e2/hc feminine 1/137 (where c is the speed of light), the parameter that describes coupling between light and relativistic electrons and that is traditionally associated with quantum electrodynamics rather than materials science. Despite being only one atom thick, graphene is found to absorb a significant (pa = 2.3%) fraction of incident white light, a consequence of graphene's unique electronic structure.
在凝聚态物理中，很少有现象仅由基本常数定义且不依赖于材料参数。例如，电阻量子h/e²（h是普朗克常数，e是电子电荷）出现在各种输运实验中，以及磁通量量子h/e，在超导物理中起着重要作用。总的来说，观察这些现象中的任何一个都需要复杂的设备和特殊的测量条件。我们表明，悬浮石墨烯的不透明度仅由精细结构常数α = e²/hc ≈ 1/137（其中c是光速）定义，该参数描述了光与相对论电子之间的耦合，传统上与量子电动力学而非材料科学相关。尽管石墨烯只有一个原子厚，但由于其独特的电子结构，它被发现会吸收相当一部分（πα = 2.3%）的入射白光。
