Angle-resolved ultraviolet photoelectron spectroscopy of the unoccupied band structure of graphite

Takahashi, Takashi; Tokailin, H.; Sagawa, T.

doi:10.1103/physrevb.32.8317

Cited by 208 publications

(132 citation statements)

References 27 publications

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“…1(b)), the band does not cross E F but stays at 2 eV around the M(L) point, indicative of the absence of FS along this direction. All these features are consistent with previous ARPES results [10,11]. It is also noted that we are able to observe separately the electronic structure along the GKM (AHL) and GM (AL) directions due to the single-crystal nature of kish graphite, which is not possible on the highly oriented pyrolytic graphite (HOPG) samples.…”

Section: Methodssupporting

confidence: 80%

Anomalous electronic states in graphite studied by angle-resolved photoemission spectroscopy

Akazaki

Kanzaki

Kobayashi

et al. 2006

Science and Technology of Advanced Materials

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We report high-resolution angle-resolved photoemission spectroscopy (ARPES) on high quality single crystal of graphite (kish graphite) to elucidate the origin of anomalous physical properties of carbon-based materials. We found an almost flat band in the vicinity of the Fermi level around the K(H) point which is not predicted by the bulk band calculation. We discuss the origin of this anomalous structure in relation to the edge-localized state on the step edges of cleaved surface. r

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Section: Methodssupporting

confidence: 80%

Anomalous electronic states in graphite studied by angle-resolved photoemission spectroscopy

Akazaki

Kanzaki

Kobayashi

et al. 2006

Science and Technology of Advanced Materials

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“…In this case, the current is dominated by BTBT current from WSe 2 to MoS 2 (denoted J W‐M in Figure 6c,d), and soon reaches saturation near the “kink” point as shown in Figure 6a. The BTBT current is positively proportional to applied V D as the BTBT window can be enlarged by increasing the bias voltage, which can be quantitatively described by45

J_{BTBT} = \frac{2 π α q}{h} \int D O S_{M} (E) D O S_{W} (E) [f_{M} (E) - f_{W} (E - q (V_{D} - I R_{S}))] d E

where α is the screening factor, q is the elementary charge, h is the Planck's constant, V D is the bias voltage, R s is the series resistance, and DOS M ( E ), DOS W ( E ), f M ( E ), and f W ( E ) represent the DOS and Fermi–Dirac distribution functions of MoS 2 and WSe 2 , respectively. Equation (2) illustrates why the position of the “kink” feature shifts along with V D .…”

Section: Resultsmentioning

confidence: 99%

Independent Band Modulation in 2D van der Waals Heterostructures via a Novel Device Architecture

et al. 2018

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Benefiting from the technique of vertically stacking 2D layered materials (2DLMs), an advanced novel device architecture based on a top‐gated MoS2/WSe2 van der Waals (vdWs) heterostructure is designed. By adopting a self‐aligned metal screening layer (Pd) to the WSe2 channel, a fixed p‐doped state of the WSe2 as well as an independent doping control of the MoS2 channel can be achieved, thus guaranteeing an effective energy‐band offset modulation and large through current. In such a device, under specific top‐gate voltages, a sharp PN junction forms at the edge of the Pd layer and can be effectively manipulated. By varying top‐gate voltages, the device can be operated under both quasi‐Esaki diode and unipolar‐Zener diode modes with tunable current modulations. A maximum gate‐coupling efficiency as high as ≈90% and a subthreshold swing smaller than 60 mV dec−1 can be achieved under the band‐to‐band tunneling regime. The superiority of the proposed device architecture is also confirmed by comparison with a traditional heterostructure device. This work demonstrates the feasibility of a new device structure based on vdWs heterostructures and its potential in future low‐power electronic and optoelectronic device applications.

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“…In fact, there is a long standing issue in regards to the carrier dynamics in graphite, that is, whether the carriers are Fermi-liquid-like or not. This question motivates experimental studies of electronic structures of these materials by using, for example, angle-resolved photoemission spectroscopy (ARPES) and one can find a long history in the ARPES studies on graphite single crystals 7,8,9,10,11,12,13,14,15 . In addition, studies of graphite-related materials such as single 16 and bilayer graphene 17 and GICs 18,19 can be found.…”

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confidence: 99%

Effect of Linear Density of States on the Quasiparticle Dynamics and Small Electron-Phonon Coupling in Graphite

Leem

Kim

et al. 2008

Phys. Rev. Lett.

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We obtained the spectral function of very high quality natural graphite single crystals using angle resolved photoelectron spectroscopy (ARPES). A clear separation of non-bonding and bonding bands and asymmetric lineshape are observed. The asymmetric lineshapes are well accounted for by the finite photoelectron escape depth and the band structure. The extracted width of the spectral function (inverse of the photohole life time) near the K point is, beyond the maximum phonon energy, approximately proportional to the energy as expected from the linear density of states near the Fermi energy. The upper bound for the electron-phonon coupling constant is about 0.2, a much smaller value than the previously reported one.PACS numbers: 74.25.Jb, 63.20.Ls, Recent discoveries of novel physical properties in carbon-based materials such as superconductivity 1,2,3,4,5 and massless Dirac Fermions 6 brought renewed interest in the electronic structure of graphite 7,8 . The peculiarity of the electronic structure of graphite has two aspects: graphite is extremely two dimensional and is a semi-metal. These facts make it fundamentally interesting to study how dimensionality affects the dynamics of the doped carriers and how the carriers in graphite intercalated compounds (GICs) couple to the mediating bosons. In fact, there is a long standing issue in regards to the carrier dynamics in graphite, that is, whether the carriers are Fermi-liquid-like or not. This question motivates experimental studies of electronic structures of these materials by using, for example, angle-resolved photoemission spectroscopy (ARPES) and one can find a long history in the ARPES studies on graphite single crystals 7,8,9,10,11,12,13,14,15 . In addition, studies of graphite-related materials such as single 16 and bilayer graphene 17 and GICs 18,19 can be found.High quality ARPES data from graphite is difficult to obtain despite graphite's two dimensional, inert nature. The problems associated with ARPES experiments on graphite are due mostly to difficulty in proper surface preparation and to some extent to the low quality of the single crystals. For example, the extreme twodimensional nature of graphite inevitably produces small flakes (many are small enough to be seen only under microscopes) on the cleaved surfaces which ruins the momentum resolution in ARPES. Such difficulties prevented one from obtaining good quality data to extract reliable information on the many-body interactions such as electron-phonon coupling (EPC). Therefore, unless such difficulties are overcome, reliable information on manybody interactions can not be extracted from the data. As a result, the experimental data in regards to the electron lifetime have been obtained mostly by time-resolved photoelectron spectroscopy on highly oriented pyrolytic graphite 20,21 .Motivated by the renewed interest in the carrier dynamics in graphite, we have performed ARPES studies on graphite single crystals. Our goal was to extract reliable quantitative information on the EPC from ARPES data. To ...

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Angle-resolved ultraviolet photoelectron spectroscopy of the unoccupied band structure of graphite

Cited by 208 publications

References 27 publications

Anomalous electronic states in graphite studied by angle-resolved photoemission spectroscopy

Anomalous electronic states in graphite studied by angle-resolved photoemission spectroscopy

Independent Band Modulation in 2D van der Waals Heterostructures via a Novel Device Architecture

Effect of Linear Density of States on the Quasiparticle Dynamics and Small Electron-Phonon Coupling in Graphite

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