First-principles calculations of dielectric and optical properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>MgB</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>

Balassis, Antonios; Chulkov, Eugene V.; Echenique, Pedro M.; Silkin, Viatcheslav M.

doi:10.1103/physrevb.78.224502

Cited by 28 publications

(27 citation statements)

References 43 publications

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“…The extinction reaches the local minimum at 600 nm (ħ 2.0 eV) and the local maximum at 1200 nm (ħ1.0 eV). The displayed dependences are in agreement with spectra of optical conductivity [19,20]. For MgB 2 , the interband contribution to the in-plane optical conductivity () contains strong IR peaks with a tail extending to the red part of the visible range and a resonance around 2.6 eV, which is close to the observed value of 2.0 eV [19].…”

Section: Sample Preparation and Characterizationsupporting

confidence: 83%

New class of photocatalytic materials and a novel principle for efficient water splitting under infrared and visible light: MgB_2 as unexpected example

Kravets

Григоренко

2015

Opt. Express

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Water splitting is unanimously recognized as environment friendly, potentially low cost and renewable energy solution based on the future hydrogen economy. Especially appealing is photocatalytic water splitting whereby a suitably chosen catalyst dramatically improves efficiency of the hydrogen production driven by direct sunlight and allows it to happen even at zero driving potential. Here, we suggest a new class of stable photocatalysts and the corresponding principle for catalytic water splitting in which infrared and visible light play the main role in producing the photocurrent and hydrogen. The new class of catalystsionic or covalent binary metals with layered graphite-like structures -effectively absorb visible and infrared light facilitating the reaction of water splitting, suppress the inverse reaction of ion recombination by separating ions due to internal electric fields existing near alternating layers, provide the sites for ion trapping of both polarities, and finally deliver the electrons and holes required to generate hydrogen and oxygen gases. As an example, we demonstrate conversion efficiency of ~27% at bias voltage V bias =0.5V for magnesium diboride working as a catalyst for photoinduced water splitting. We discuss its advantages over some existing materials and propose the underlying mechanism of photocatalytic water splitting by binary layered metals.

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Section: Sample Preparation and Characterizationsupporting

confidence: 83%

New class of photocatalytic materials and a novel principle for efficient water splitting under infrared and visible light: MgB_2 as unexpected example

Kravets

Григоренко

2015

Opt. Express

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“…Note how the IP peak starting from Q = 2π/c = 1.389Å −1 closely follows the dispersion of the IP mode. This phenomenon was in details explained for the cases of MgB 2 , 63,64 graphite, 58 and compressed Li. 65 Note that the complete disappearance and subsequent reappearance of this mode with momentum transfer increase resembles the case of compressed lithium 65 and not the one of MgB 2 where continuous dispersion over subsequent BZ's is observed.…”

Section: Calculation Results and Discussionmentioning

confidence: 66%

Low-energy plasmonic structure in CaC6

et al. 2012

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The low-energy dielectric properties of CaC 6 -a representative graphite intercalated compound (GIC)-were investigated by ab initio time-dependent density functional theory calculations with full inclusion of local field effects. The calculations predict the existence of several kinds of plasmons in CaC 6 with energy below 10 eV. The mode with the largest energy is a conventional "πp" mode strongly dispersing in the hexagonal basal plane and almost nondispersing in the perpendicular direction. In the 2.3-3 eV energy range, we find a long-lived intraband plasmon with negative (positive) dispersion with momentum transfer in (perpendicular to) the basal plane. In the 0-1.5 eV energy range, a mode with linear soundlike dispersion along all three high-symmetry directions is observed. All the three modes present strong anisotropy originated from the band structure. The physical origin of these excitation modes is discussed in terms of intra-and interband transitions. The crucial role of local field effects in the propagation of the two lowest-energy modes at large momentum transfers and in the determination of its dispersion over extended momentum-transfer region is analyzed.

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“…Remarkably, the low-energy plasmon of MgB 2 also shows a weak influence of LFE for momenta in the 1BZ. 21,35,36 Although in the 1BZ LFEs do not modify dramatically the plasmon dispersion, they are crucial to make the undamped plasmon reappear beyond the 1BZ as it happens in MgB 2 . 21 In fact, no resonant peak is observed in the loss function when the inversion is performed as in Eq.…”

Section: Resultsmentioning

confidence: 99%

Electronic collective excitations in compressed lithium fromab initiocalculations: Importance and anisotropy of local-field effects at large momenta

et al. 2010

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According to our ab initio calculations, the recently reported undamped plasmon in compressed fcc lithium emerges not only due to the fact that the dielectric matrix determinant vanishes at long wavelengths at the plasmon energy, i.e., satisfying the ideal condition for an undamped plasmon in a crystal but also extends at large momenta specially along the ⌫L direction. Different from the case of simple metals, the local-field effects dominate, leading to the striking periodicity exhibited by the low-energy plasmon for momentum transfers beyond the first Brillouin zone. Remarkably, pressure-induced electronic anisotropy and localization increase the impact of local-field effects on the electronic response even in the compact fcc structure. Interestingly, the importance of local-field effects is similar in lithium under pressure and in materials with confined geometries such as MgB 2 .

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First-principles calculations of dielectric and optical properties ofMgB2

Cited by 28 publications

References 43 publications

New class of photocatalytic materials and a novel principle for efficient water splitting under infrared and visible light: MgB_2 as unexpected example

New class of photocatalytic materials and a novel principle for efficient water splitting under infrared and visible light: MgB_2 as unexpected example

Low-energy plasmonic structure in CaC6

Electronic collective excitations in compressed lithium fromab initiocalculations: Importance and anisotropy of local-field effects at large momenta

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