Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

The rise of graphene

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.

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The electronic properties of graphene

Quantum electrodynamics (resulting from the merger of quantum mechanics and relativity theory) has provided a clear understanding of phenomena ranging from particle physics to cosmology and from astrophysics to quantum chemistry. The ideas underlying quantum electrodynamics also influence the theory of condensed matter, but quantum relativistic effects are usually minute in the known experimental systems that can be described accurately by the non-relativistic Schrodinger equation. Here we report an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation. The charge carriers in graphene mimic relativistic particles with zero rest mass and have an effective 'speed of light' c* approximately 10(6) m s(-1). Our study reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions. In particular we have observed the following: first, graphene's conductivity never falls below a minimum value corresponding to the quantum unit of conductance, even when concentrations of charge carriers tend to zero; second, the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; and third, the cyclotron mass m(c) of massless carriers in graphene is described by E = m(c)c*2. This two-dimensional system is not only interesting in itself but also allows access to the subtle and rich physics of quantum electrodynamics in a bench-top experiment.

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Two-dimensional gas of massless Dirac fermions in graphene

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

The morphology and stoichiometry of a model iron oxide magnetic tunneling junction heterostructure has been investigated using x-ray photoemission electron microscopy (X-PEEM) and atomic force microscopy (AFM). AFM data evidence islands of width a few μ m and height 10 nm. X-PEEM data show that two types of iron oxide are present, the islands being Fe3O4(111) and the terraces α-Fe2O3(0001). The Fe3O4(111) islands appear as dark areas in X-PEEM, which is attributed to difference in work function and/or mean free path of the two iron oxide phases.

Photoemission electron microscopy and atomic force microscopy of epitaxial iron oxide films on a-Al2O3(0001)

Spin asymmetries in inverse photoemission from PbS(100)

We present composite plasmonic nanostructures designed to achieve cascaded enhancement of electromagnetic fields at optical frequencies. Our structures are made with the help of electron beam lithography and comprise a set of self-similar metallic nano-discs placed one above another. The optical properties of reproducible arrays of these structures are studied using scanning confocal Raman spectroscopy. We observe significant (up to 1000 times) enhancements of resonant Raman scattering from a graphene layer generated by near-fields of a plasmonic nanoarray. This enhancement is quantitatively explained by the electromagnetic mechanism.

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Optical field enhancement in composite plasmonic nanostruc- tures: gold dots with graphene and dye R6G

Graphene is a two dimensional, one-atom thick layer of carbon atoms with many exceptional properties [1]. Plasmonics allows manipulation of light at the nanometer scale, with potential applications for super-fast, subwavelength optics [2]. Incorporating graphene into plasmonic metamaterials has potential applications for novel active optical devices, exploiting the high sensitivity of graphene to bias voltage to enable control of the plasmonic resonances. This work demonstrates that the coupling of the localized surface plasmon resonances of closely- spaced metallic nanostripes is significantly modified by the presence of a graphene layer. The resonances in question lie in the visible and near infra-red, important areas for many applications. We propose that the observed effect is due to resistive coupling of the metallic stripes through the highly conductive graphene layer

Fred Schedin

Papers

Photoemission electron microscopy and atomic force microscopy of epitaxial iron oxide films on a-Al2O3(0001)

Spin asymmetries in inverse photoemission from PbS(100)

Optical field enhancement in composite plasmonic nanostruc- tures: gold dots with graphene and dye R6G

Resistive coupling of localized plasmon resonances in metallic nanostripes through a graphene layer