Showing papers on "Bilayer graphene published in 2007"
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TL;DR: 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 can now be mimicked and tested in table-top experiments.
Abstract: 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.
35,293 citations
TL;DR: These studies by transmission electron microscopy reveal that individual graphene sheets freely suspended on a microfabricated scaffold in vacuum or air are not perfectly flat: they exhibit intrinsic microscopic roughening such that the surface normal varies by several degrees and out-of-plane deformations reach 1 nm.
Abstract: Graphene — a recently isolated one-atom-thick layered form of graphite — is a hot topic in the materials science and condensed matter physics communities, where it is proving to be a popular model system for investigation. An experiment involving individual graphene sheets suspended over a microscale scaffold has allowed structure determination using transmission electron microscopy and diffraction, perhaps paving the way towards an answer to the question of why graphene can exist at all. The 'two-dimensional' sheets, it seems, are not flat, but wavy. The undulations are less pronounced in a two-layer system, and disappear in multilayer samples. Learning more about this 'waviness' may reveal what makes these extremely thin carbon membranes so stable. Investigations of individual graphene sheets freely suspended on a microfabricated scaffold in vacuum or in air reveal that the membranes are not perfectly flat, but exhibit an intrinsic waviness, such that the surface normal varies by several degrees, and out-of-plane deformations reach 1 nm. The recent discovery of graphene has sparked much interest, thus far focused on the peculiar electronic structure of this material, in which charge carriers mimic massless relativistic particles1,2,3. However, the physical structure of graphene—a single layer of carbon atoms densely packed in a honeycomb crystal lattice—is also puzzling. On the one hand, graphene appears to be a strictly two-dimensional material, exhibiting such a high crystal quality that electrons can travel submicrometre distances without scattering. On the other hand, perfect two-dimensional crystals cannot exist in the free state, according to both theory and experiment4,5,6,7,8,9. This incompatibility can be avoided by arguing that all the graphene structures studied so far were an integral part of larger three-dimensional structures, either supported by a bulk substrate or embedded in a three-dimensional matrix1,2,3,9,10,11,12. Here we report on individual graphene sheets freely suspended on a microfabricated scaffold in vacuum or air. These membranes are only one atom thick, yet they still display long-range crystalline order. However, our studies by transmission electron microscopy also reveal that these suspended graphene sheets are not perfectly flat: they exhibit intrinsic microscopic roughening such that the surface normal varies by several degrees and out-of-plane deformations reach 1 nm. The atomically thin single-crystal membranes offer ample scope for fundamental research and new technologies, whereas the observed corrugations in the third dimension may provide subtle reasons for the stability of two-dimensional crystals13,14,15.
4,653 citations
Journal Article•
TL;DR: It is shown that in graphene, in a single atomic layer of carbon, the QHE can be measured reliably even at room temperature, which makes possible QHE resistance standards becoming available to a broader community, outside a few national institutions.
Abstract: The quantum Hall effect (QHE), one example of a quantum phenomenon that occurs on a truly macroscopic scale, has attracted intense interest since its discovery in 1980 and has helped elucidate many important aspects of quantum physics. It has also led to the establishment of a new metrological standard, the resistance quantum. Disappointingly, however, the QHE has been observed only at liquid-helium temperatures. We show that in graphene, in a single atomic layer of carbon, the QHE can be measured reliably even at room temperature, which makes possible QHE resistance standards becoming available to a broader community, outside a few national institutions.
2,404 citations
TL;DR: Electric conductivity measurements indicate a 10000-fold increase in conductivity after chemical reduction to graphene, and temperature-dependent conductivity indicates that the graphene-like sheets exhibit semiconducting behavior.
Abstract: Oxidation of graphite produces graphite oxide, which is dispersible in water as individual platelets. After deposition onto Si/SiO2 substrates, chemical reduction produces graphene sheets. Electrical conductivity measurements indicate a 10000-fold increase in conductivity after chemical reduction to graphene. Tapping mode atomic force microscopy measurements show one to two layer graphene steps. Electrodes patterned onto a reduced graphite oxide film demonstrate a field effect response when the gate voltage is varied from +15 to −15 V. Temperature-dependent conductivity indicates that the graphene-like sheets exhibit semiconducting behavior.
1,918 citations
TL;DR: It is demonstrated that the electronic gap of a graphene bilayer can be controlled externally by applying a gate bias and can be changed from zero to midinfrared energies by using fields of less, approximately < 1 V/nm, below the electric breakdown of SiO2.
Abstract: We demonstrate that the electronic gap of a graphene bilayer can be controlled externally by applying a gate bias. From the magnetotransport data (Shubnikov-de Haas measurements of the cyclotron mass), and using a tight-binding model, we extract the value of the gap as a function of the electronic density. We show that the gap can be changed from zero to midinfrared energies by using fields of less, approximately < 1 V/nm, below the electric breakdown of SiO2. The opening of a gap is clearly seen in the quantum Hall regime.
1,557 citations
TL;DR: Atomic structures and nanoscale morphology of graphene-based electronic devices are revealed for the first time and a strong spatially dependent perturbation is revealed which breaks the hexagonal lattice symmetry of the graphitic lattice.
Abstract: We employ scanning probe microscopy to reveal atomic structures and nanoscale morphology of graphene-based electronic devices (i.e., a graphene sheet supported by an insulating silicon dioxide substrate) for the first time. Atomic resolution scanning tunneling microscopy images reveal the presence of a strong spatially dependent perturbation, which breaks the hexagonal lattice symmetry of the graphitic lattice. Structural corrugations of the graphene sheet partially conform to the underlying silicon oxide substrate. These effects are obscured or modified on graphene devices processed with normal lithographic methods, as they are covered with a layer of photoresist residue. We enable our experiments by a novel cleaning process to produce atomically clean graphene sheets.
1,497 citations
Journal Article•
TL;DR: In this paper, the electronic gap of a graphene bilayer can be controlled externally by applying a gate bias, and the gap can be changed from zero to mid-infrared energies by using fields of less, approximately < 1 V/nm, below the electric breakdown of SiO2.
Abstract: We demonstrate that the electronic gap of a graphene bilayer can be controlled externally by applying a gate bias. From the magnetotransport data (Shubnikov-de Haas measurements of the cyclotron mass), and using a tight-binding model, we extract the value of the gap as a function of the electronic density. We show that the gap can be changed from zero to midinfrared energies by using fields of less, approximately < 1 V/nm, below the electric breakdown of SiO2. The opening of a gap is clearly seen in the quantum Hall regime.
1,365 citations
TL;DR: A graphene bilayer with a relative small angle rotation between the layers is considered and it is found that the low energy dispersion is linear, as in a single layer, but the Fermi velocity can be significantly smaller than the single-layer value.
Abstract: We consider a graphene bilayer with a relative small angle rotation between the layers--a stacking defect often seen in the surface of graphite--and calculate the electronic structure near zero energy in a continuum approximation. Contrary to what happens in an AB stacked bilayer and in accord with observations in epitaxial graphene, we find: (a) the low energy dispersion is linear, as in a single layer, but the Fermi velocity can be significantly smaller than the single-layer value; (b) an external electric field, perpendicular to the layers, does not open an electronic gap.
1,277 citations
TL;DR: It is argued that the experimentally observed saturation of conductivity at low density arises from the charged impurity induced inhomogeneity in the graphene carrier density which becomes severe for n less, similarn(i) approximately 10(12) cm(-2).
Abstract: Carrier transport in gated 2D graphene monolayers is considered in the presence of scattering by random charged impurity centers with density n(i). Excellent quantitative agreement is obtained (for carrier density n>10(12) cm(-2)) with existing experimental data. The conductivity scales linearly with n/n(i) in the theory. We explain the experimentally observed asymmetry between electron and hole conductivities, and the high-density saturation of conductivity for the highest mobility samples. We argue that the experimentally observed saturation of conductivity at low density arises from the charged impurity induced inhomogeneity in the graphene carrier density which becomes severe for n less, similarn(i) approximately 10(12) cm(-2).
1,163 citations
TL;DR: Light is shed on the special role of time reversal symmetry in graphene, and phase coherent electronic transport at the Dirac point is demonstrated, finding that not only the normal state conductance of graphene is finite, but also a finite supercurrent can flow at zero charge density.
Abstract: Graphene--a recently discovered form of graphite only one atomic layer thick--constitutes a new model system in condensed matter physics, because it is the first material in which charge carriers behave as massless chiral relativistic particles. The anomalous quantization of the Hall conductance, which is now understood theoretically, is one of the experimental signatures of the peculiar transport properties of relativistic electrons in graphene. Other unusual phenomena, like the finite conductivity of order 4e(2)/h (where e is the electron charge and h is Planck's constant) at the charge neutrality (or Dirac) point, have come as a surprise and remain to be explained. Here we experimentally study the Josephson effect in mesoscopic junctions consisting of a graphene layer contacted by two closely spaced superconducting electrodes. The charge density in the graphene layer can be controlled by means of a gate electrode. We observe a supercurrent that, depending on the gate voltage, is carried by either electrons in the conduction band or by holes in the valence band. More importantly, we find that not only the normal state conductance of graphene is finite, but also a finite supercurrent can flow at zero charge density. Our observations shed light on the special role of time reversal symmetry in graphene, and demonstrate phase coherent electronic transport at the Dirac point.
1,081 citations
TL;DR: The realization of a single-layer graphene p-n junction is reported in which carrier type and density in two adjacent regions are locally controlled by electrostatic gating, consistent with recent theory.
Abstract: The unique band structure of graphene allows reconfigurable electric-field control of carrier type and density, making graphene an ideal candidate for bipolar nanoelectronics. We report the realization of a single-layer graphene p-n junction in which carrier type and density in two adjacent regions are locally controlled by electrostatic gating. Transport measurements in the quantum Hall regime reveal new plateaus of two-terminal conductance across the junction at 1 and \({3}/{2}\) times the quantum of conductance, e 2 /h , consistent with recent theory. Beyond enabling investigations in condensed-matter physics, the demonstrated local-gating technique sets the foundation for a future graphene-based bipolar technology.
TL;DR: In this article, a strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC.
Abstract: A strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over]) 4H-SiC surfaces. We also present evidence of a charge transfer that depends on the interface geometry. Hence the graphene is doped and a gap opens at the Dirac point after three Bernal stacked carbon layers are formed.
TL;DR: By performing low-temperature transport spectroscopy on single-layer and bilayer graphene, ballistic propagation and quantum interference of multiply reflected waves of charges from normal electrodes and multiple Andreev reflections from superconducting electrodes are observed, thereby realizing quantum billiards in which scattering only occurs at the boundaries.
Abstract: As an emergent electronic material and model system for condensed-matter physics, graphene and its electrical transport properties have become a subject of intense focus. By performing low-temperature transport spectroscopy on single-layer and bilayer graphene, we observe ballistic propagation and quantum interference of multiply reflected waves of charges from normal electrodes and multiple Andreev reflections from superconducting electrodes, thereby realizing quantum billiards in which scattering only occurs at the boundaries. In contrast to the conductivity of conventional two-dimensional materials, graphene's conductivity at the Dirac point is geometry-dependent because of conduction via evanescent modes, approaching the theoretical value 4e(2)/pih (where e is the electron charge and h is Planck's constant) only for short and wide devices. These distinctive transport properties have important implications for understanding chaotic quantum systems and implementing nanoelectronic devices, such as ballistic transistors.
TL;DR: In this paper, the authors reported low-temperature scanning tunnelling spectra of graphite subjected to a magnetic field of up to 12'T and found evidence for the coexistence of both massless and massive Dirac fermions in graphite.
Abstract: The unique electronic behaviour of monolayer and bilayer graphene1,2 is a result of the unusual quantum-relativistic characteristics of the so-called ‘Dirac fermions’ (DFs) that carry charge in these materials. Although DFs in monolayer graphene move as if they were massless, and in bilayer graphene they do so with non-zero mass, all DFs show chirality, which gives rise to an unusual Landau level (LL) energy spectrum3,4,5,6,7,8,9,10,11 and the observation of an anomalous quantum Hall effect in both types of graphene4,5,8. Here we report low-temperature scanning tunnelling spectra of graphite subjected to a magnetic field of up to 12 T, which provide the first direct observations of the LLs that produce such behaviour. Unexpectedly, we find evidence for the coexistence of both massless and massive DFs in graphite, and confirm the quantum-relativistic nature of these quasiparticles through the appearance of a zero-energy LL.
TL;DR: In this paper, the electronic structure of bilayer graphene was investigated from a resonant Raman study of the band using different laser excitation energies, revealing the difference of the effective masses of electrons and holes.
Abstract: The electronic structure of bilayer graphene is investigated from a resonant Raman study of the ${G}^{\ensuremath{'}}$ band using different laser excitation energies. The values of the parameters of the Slonczewski-Weiss-McClure model for bilayer graphene are obtained from the analysis of the dispersive behavior of the Raman features, and reveal the difference of the effective masses of electrons and holes. The splitting of the two TO phonon branches in bilayer graphene is also obtained from the experimental data. Our results have implications for bilayer graphene electronic devices.
TL;DR: Graphene is the first example of truly two-dimensional crystals - it's just one layer of carbon atoms as mentioned in this paper and it turns out that graphene is a gapless semiconductor with unique electronic properties resulting from the fact that charge carriers in graphene obey linear dispersion relation.
Abstract: Graphene is the first example of truly two-dimensional crystals - it's just one layer of carbon atoms. It turns out that graphene is a gapless semiconductor with unique electronic properties resulting from the fact that charge carriers in graphene obey linear dispersion relation, thus mimicking massless relativistic particles. This results in the observation of a number of very peculiar electronic properties - from an anomalous quantum Hall effect to the absence of localization. It also provides a bridge between condensed matter physics and quantum electrodynamics and opens new perspectives for carbon-based electronics. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
TL;DR: In this paper, the authors analyzed the spectroscopic features of bilayer graphene determined by the formation of pairs of low-energy and split bands in this material and showed that the inter-Landau-level absorption spectrum in bilayer GPs at high magnetic field is much denser in the far-infrared range than that in monolayer material and that the polarization dependence of its lowest energy peak can be used to test the form of the bilayer ground state in the quantum Hall-effect regime.
Abstract: We analyze the spectroscopic features of bilayer graphene determined by the formation of pairs of low-energy and split bands in this material. We show that the inter-Landau-level absorption spectrum in bilayer graphene at high magnetic field is much denser in the far-infrared range than that in monolayer material and that the polarization dependence of its lowest-energy peak can be used to test the form of the bilayer ground state in the quantum Hall-effect regime.
TL;DR: In this paper, the optical visibility of monolayer and bilayer graphene was modeled on a SiO2∕Si substrate or thermally annealed on the surface of SiC.
Abstract: The authors model the optical visibility of monolayer and bilayer graphene deposited on a SiO2∕Si substrate or thermally annealed on the surface of SiC. Visibility is much stonger in reflection than in transmission, reaching the optimum conditions when the bare substrate transmits light resonantly. In the optical range of frequencies a bilayer is approximately twice as visible as a monolayer thereby making the two types of graphene distinguishable from each other.
TL;DR: In this article, a scanning-tunneling microscopy (STM) study of a gently graphitized $6H\text{\ensuremath{-}}\mathrm{Si}\mathrm {C}(0001)$ surface in ultrahigh vacuum is presented.
Abstract: We present a scanning-tunneling microscopy (STM) study of a gently graphitized $6H\text{\ensuremath{-}}\mathrm{Si}\mathrm{C}(0001)$ surface in ultrahigh vacuum. From an analysis of atomic scale images, we identify two different kinds of terraces, which we attribute to mono- and bilayer graphene capping a C-rich interface. At low temperature, both terraces show $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})$ quantum interferences generated by static impurities. Such interferences are a fingerprint of $\ensuremath{\pi}$-like states close to the Fermi level. We conclude that the metallic states of the first graphene layer are almost unperturbed by the underlying interface, in agreement with recent photoemission experiments [Bostwick et al., Nat. Phys. 3, 36 (2007)].
TL;DR: In this article, the authors studied the transport properties of charge carriers through graphene superlattices consisting of monolayer or bilayer graphene on the basis of the transfer-matrix method.
Abstract: This paper studies the transport properties of charge carriers through graphene superlattices consisting of monolayer or bilayer graphene on the basis of the transfer-matrix method. Emphasis is placed on the relationship between the Klein paradox and resonant tunneling in double-barrier junctions. It is shown that normal incidence transmission probabilities for two kinds of graphene structure exhibit different features. Independent of structure parameters, they are always perfectly transmitted in a monolayer graphene structure. In contrast, the transmission resonances occur in a bilayer graphene structure. However, the angularly averaged conductivities for both depend on the thickness and height of the barriers as well as the width and number of the well. That is to say, the angularly averaged conductivities in monolayer and bilayer graphene superlattices can be controlled by changing the structure parameters even if Klein tunneling exists.
TL;DR: In this article, a scanning tunneling spectroscopy (STS) study of the local electronic structure of single and bilayer graphene grown epitaxially on a SiC(0001) surface is presented.
Abstract: We present a scanning tunneling spectroscopy (STS) study of the local electronic structure of single and bilayer graphene grown epitaxially on a SiC(0001) surface. Low voltage topographic images reveal fine, atomic-scale carbon networks, whereas higher bias images are dominated by emergent spatially inhomogeneous large-scale structure similar to a carbon-rich reconstruction of SiC(0001). STS spectroscopy shows a ~100meV gap-like feature around zero bias for both monolayer and bilayer graphene/SiC, as well as significant spatial inhomogeneity in electronic structure above the gap edge. Nanoscale structure at the SiC/graphene interface is seen to correlate with observed electronic spatial inhomogeneity. These results are important for potential devices involving electronic transport or tunneling in graphene/SiC.
Journal Article•
TL;DR: In this article, the effects of disorder in the electronic properties of graphene multilayers, with special focus on the bilayer and the infinite stack, have been studied, and it is shown that at low energies and long wavelengths, the electronic self-energies and density of states exhibit behavior with divergences near half filling.
Abstract: We study the effects of disorder in the electronic properties of graphene multilayers, with special focus on the bilayer and the infinite stack. At low energies and long wavelengths, the electronic self-energies and density of states exhibit behavior with divergences near half filling. As a consequence, the spectral functions and the conductivities acquire anomalous properties. In particular, we show that the quasiparticle decay rate has a minimum as a function of energy, there is a universal minimum value for the in-plane conductivity of order e(2)/h per plane and, unexpectedly, the c-axis conductivity is enhanced by disorder at low doping, leading to an enormous conductivity anisotropy at low temperatures.
TL;DR: In this article, the authors present a scanning tunneling spectroscopy (STS) study of the local electronic structure of single and bilayer graphene grown epitaxially on a SiC(0001) surface.
Abstract: The authors present a scanning tunneling spectroscopy (STS) study of the local electronic structure of single and bilayer graphene grown epitaxially on a SiC(0001) surface Low voltage topographic images reveal fine, atomic-scale carbon networks, whereas higher bias images are dominated by emergent spatially inhomogeneous large-scale structure similar to a carbon-rich reconstruction of SiC(0001) STS spectroscopy shows an ∼100meV gaplike feature around zero bias for both monolayer and bilayer graphene/SiC, as well as significant spatial inhomogeneity in electronic structure above the gap edge Nanoscale structure at the SiC/graphene interface is seen to correlate with observed electronic spatial inhomogeneity These results are relevant for potential devices involving electronic transport or tunneling in graphene/SiC
TL;DR: It is shown that a negative magnetoresistance--a signature of weak localization--is observed at different carrier densities, including the electroneutrality region, and it is controlled not only by the dephasing time, but also by different elastic processes that break the effective time-reversal symmetry and provide intervalley scattering.
Abstract: We have performed the first experimental investigation of quantum interference corrections to the conductivity of a bilayer graphene structure. A negative magnetoresistance--a signature of weak localization--is observed at different carrier densities, including the electroneutrality region. It is very different, however, from the weak localization in conventional two-dimensional systems. We show that it is controlled not only by the dephasing time, but also by different elastic processes that break the effective time-reversal symmetry and provide intervalley scattering.
TL;DR: In this paper, the temperature coefficients for the G and 2D-band frequencies extracted from Raman spectra of the single-layer graphene are −(1.6±0.04)×10−2cm−1∕K and −(3.4±
Abstract: Raman microscopy of graphene was carried out over the temperature range from 83to373K. The number of layers was independently confirmed by the quantum Hall measurements and atomic force microscopy. The values of the temperature coefficients for the G and 2D-band frequencies extracted from Raman spectra of the single-layer graphene are −(1.6±0.2)×10−2cm−1∕K and −(3.4±0.4)×10−2cm−1∕K, respectively. The G peak temperature coefficients of the bilayer graphene and bulk graphite are −(1.5±0.06)×10−2cm−1∕K and −(1.1±0.04)×10−2cm−1∕K, respectively. The results are important for the application of Raman microscopy as a nanometrology tool for the graphene-based devices operating at various temperatures.
TL;DR: Calculations with hybrid density functional demonstrate that finite graphene ribbons behave as half-semiconductors, showing that the spin-dependent band gap can be changed in a wide range, making possible many applications in spintronics.
Abstract: Band gap studies of zigzag-edge graphene ribbons are presented. While earlier calculations at LDA level show that zigzag-edge graphene ribbons become half-metallic when cross-ribbon electric fields are applied, our calculations with hybrid density functional demonstrate that finite graphene ribbons behave as half-semiconductors. The spin-dependent band gap can be changed in a wide range, making possible many applications in spintronics.
TL;DR: In this article, the authors review the tight-binding model of bilayer graphene which determines the band structure and low energy quasiparticle properties of this material and describe the optical manifestation of the existence of a pair of split-bands and low-energy branches in the bilayer spectrum.
TL;DR: In this paper, position-dependent quantum dot doping is used to break the equivalence between the upper and lower layers of a bilayers of graphene and lift the degeneracy of the positive and negative momentum states of the dot.
Abstract: We demonstrate theoretically that quantum dots in bilayers of graphene can be realized. A position-dependent doping breaks the equivalence between the upper and lower layer and lifts the degeneracy of the positive and negative momentum states of the dot. Numerical results show the simultaneous presence of electron and hole confined states for certain doping profiles and a remarkable angular momentum dependence of the quantum dot spectrum, which is in sharp contrast with that for conventional semiconductor quantum dots. We predict that the optical spectrum will consist of a series of nonequidistant peaks.
TL;DR: In this paper, the authors reported a strong field effect observed at room temperature in epitaxially synthesized, as opposed to exfoliated, graphene, which was photolithographically patterned into isolated active regions for the semimetal graphene-based transistors.
Abstract: The authors report a strong field effect observed at room temperature in epitaxially synthesized, as opposed to exfoliated, graphene. The graphene formed on the silicon face of a 4H silicon carbide substrate was photolithographically patterned into isolated active regions for the semimetal graphene-based transistors. Gold electrodes and a polymer dielectric were used in the top-gate transistors. The demonstration of a field effect mobility of 535cm2∕Vs was attributed to the transistor geometry that maximizes conductance modulation, although the mobility is lower than observed in exfoliated graphene possibly due to grain boundaries caused by the rough morphology of the substrate surface.
TL;DR: In this article, it was demonstrated that the quasiparticle dynamics, the layer-dependent charge and potential, and the c-axis screening coefficient could be extracted from measurements of the spectral function of few layer graphene films grown epitaxially on SiC using angle-resolved photoemission spectroscopy (ARPES).
Abstract: Recently, it was demonstrated that the quasiparticle dynamics, the layer-dependent charge and potential, and the c-axis screening coefficient could be extracted from measurements of the spectral function of few layer graphene films grown epitaxially on SiC using angle-resolved photoemission spectroscopy (ARPES). In this paper we review these findings, and present detailed methodology for extracting such parameters from ARPES. We also present detailed arguments against the possibility of an energy gap at the Dirac crossing ED.