Topic
Brillouin zone
About: Brillouin zone is a research topic. Over the lifetime, 13849 publications have been published within this topic receiving 383077 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: The spin-wave dispersion relation is asymmetric with respect to wave vector inversion for a variety of ferromagnetic films with Dzyaloshinskii-Moriya interactions and different crystallographic classes and it is predicted that, for non-zero wave vectors, the resonance frequency and resonance field can increase or decrease depending on thespin-wave vector orientation.
Abstract: We have developed a theory that describes the spin-wave spectra of ferromagnetic films with Dzyaloshinskii–Moriya interactions. In agreement with recent experiments (Zakeri et al 2010 Phys. Rev. Lett. 104 137203), we demonstrate that the spin-wave dispersion relation is asymmetric with respect to wave vector inversion for a variety of ferromagnetic films with Dzyaloshinskii–Moriya interactions and different crystallographic classes. It is also predicted that, for non-zero wave vectors, the resonance frequency and resonance field can increase or decrease depending on the spin-wave vector orientation. We provide explicit formulas for the spin-wave dispersion relation and its asymmetry, as well as for the dynamic susceptibility for a film under microwave excitation, that can be used to understand ferromagnetic resonance as well as Brillouin light scattering experiments in these classes of magnetic thin films.
159 citations
TL;DR: A study of the valence band dispersion of twisted bilayer graphene using angle-resolved photoemission spectroscopy and ab initio calculations finds minigaps appeared at the Brillouin zone boundaries of the moiré superlattice formed by the misorientation of the two graphene layers.
Abstract: We report a study of the valence band dispersion of twisted bilayer graphene using angle-resolved photoemission spectroscopy and ab initio calculations. We observe two noninteracting cones near the Dirac crossing energy and the emergence of van Hove singularities where the cones overlap for large twist angles (>5°). Besides the expected interaction between the Dirac cones, minigaps appeared at the Brillouin zone boundaries of the moire superlattice formed by the misorientation of the two graphene layers. We attribute the emergence of these minigaps to a periodic potential induced by the moire. These anticrossing features point to coupling between the two graphene sheets, mediated by moire periodic potentials.
158 citations
TL;DR: The electronic and optical properties of Pb Se quantum dots are calculated using an atomistic pseudopotential method, finding that the electronic structure is different from that of ordinary II-VI's and, at the same time, is more subtle than what k.p or tight-binding calculations have suggested previously for PbSe.
Abstract: PbSe is a pseudo-II-VI material distinguished from ordinary II-VI's (e.g., CdSe, ZnSe) by having both its valence band maximum (VBM) and its conduction band minimum (CBM) located at the fourfold-degenerate L-point in the Brillouin zone. It turns out that this feature dramatically affects the properties of the nanosystem. We have calculated the electronic and optical properties of PbSe quantum dots using an atomistic pseudopotential method, finding that the electronic structure is different from that of ordinary II-VI's and, at the same time, is more subtle than what k·p or tight-binding calculations have suggested previously for PbSe. We find the following in PbSe dots: (i) The intraband (valence-to-valence and conduction-to-conduction) as well as interband (valence-to-conduction) excitations involve the massively split L-manifold states. (ii) In contrast to previous suggestions that the spacings between valence band levels will equal those between conduction band levels (because the corresponding effect...
158 citations
TL;DR: The valence band structure of the layered transition metal dichalcogenide has been determined experimentally by angle resolved photoelectron spectroscopy and theoretically by augmented spherical wave band structure calculations as based on density functional theory as mentioned in this paper.
Abstract: The valence band structure of the layered transition metal dichalcogenide ${\mathrm{WS}}_{2}$ has been determined experimentally by angle resolved photoelectron spectroscopy and theoretically by augmented spherical wave band structure calculations as based on density functional theory. Good agreement between experimental and calculated band structure is observed for single crystal ${\mathrm{WS}}_{2}.$ An experimental band structure of a single layer was determined from an electronically decoupled film prepared on a single crystalline graphite substrate by metal-organic van der Waals epitaxy. The polarization dependent photoemission selection rules of the single layer film are appropriate for a free standing film. The experimental single layer band structure shows some differences compared to band structure calculations using bulk atomic positions within the layer. We conclude that relaxation of the single layer occurs as a consequence of the missing interlayer interactions leading to close agreement between electronic structure of the single layer and single crystal. As a consequence of the missing interlayer interactions the valence band maximum for the single layer is located at the K point of the Brillouin zone.
157 citations
TL;DR: In a subwavelength-diameter optical fibre, the first experimental observation of Brillouin light scattering from surface acoustic waves is reported, which opens new opportunities for various sensing applications, not only in microwave photonics and nonlinear plasmonics.
Abstract: In optical fibres, stimulated Brillouin scattering is a fundamental interaction where light generates bulk elastic waves and it is backward scattered by them. Here, Beugnot et al. demonstrate the generation of backward-propagating surface acoustic wave Brillouin scattering in subwavelength-diameter optical fibres.
157 citations