Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.3928/0191-3913-20021101-03 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Why does silicon have an indirect band gap?
Mater Horiz
January 2025
Department of Materials Science, University of Michigan, Ann Arbor, Michigan 48109, USA.
It is difficult to intuit how electronic structure features-such as band gap magnitude, location of band extrema, effective masses, -arise from the underlying crystal chemistry of a material. Here we present a strategy to distill sparse and chemically-interpretable tight-binding models from density functional theory calculations, enabling us to interpret how multiple orbital interactions in a 3D crystal conspire to shape the overall band structure. Applying this process to silicon, we show that its indirect gap arises from a competition between first and second nearest-neighbor bonds-where second nearest-neighbor interactions pull the conduction band down from Γ to X in a cosine shape, but the first nearest-neighbor bonds push the band up near X, resulting in the characteristic dip of the silicon conduction band.
View Article and Find Full Text PDFOrbital angular momentum (OAM), with its unique orthogonality, is widely applied in optical holographic encryption and information storage. Theoretically, the topological charge of OAM holography is infinite. However, in practice, it is restricted by the Nyquist-Shannon sampling theorem and experimental equipment, resulting in a relatively small number of practically usable channels.
View Article and Find Full Text PDFA transversely isotropic diode-pumped solid-state laser is used to obtain an orthogonally dual-polarization nonplanar circular mode (NCM) under off-axis pumping in the strictly degenerate cavity. Each polarized component of the NCM outside the cavity is revealed to be individually localized on the ray orbits forming a nonplanar surface, in which the transverse patterns display multiple spots well positioned on a circular structure. An analytical representation is established to explore polarization-resolved components of the NCM by utilizing the Gaussian wave packet to directly correlate with geometrical rays.
View Article and Find Full Text PDFInfrared Ion Spectroscopy of Gaseous [Cu(2,2'-Bipyridine)]: Investigation of Jahn-Teller Elongation Versus Compression.
J Phys Chem A
January 2025
Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
Symmetry breaking is ubiquitous in chemical transformations and affects various physicochemical properties of materials and molecules; Jahn-Teller (JT) distortion of hexa-coordinated transition-metal-ligand complexes falls within this paradigm. An uneven occupancy of degenerate 3d-orbitals forces the complex to adopt an axially elongated or compressed geometry, lowering the symmetry of the system and lifting the degeneracy. Coordination complexes of Cu are known to exhibit axial elongation, while compression is far less common, although this may be due to the lack of rigorous experimental verification.
View Article and Find Full Text PDFIn this paper we propose an information encoding method based on a segmented vortex beam. The segmented vortex beam with a single uniform-intensity ring and a combination of multiple topological charges is designed for information encoding. The radius of the beam can be designed to be arbitrary, with multiple orbital angular momentum states superimposed along the ring.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!