Results 141 to 150 of about 4,112,115 (294)

Nanoscale Optical Inhomogeneities From Compositional Segregation Within Individual GaN‐on‐Si Quantum Wells

open access: yesAdvanced Science, EarlyView.
This work visualizes local variations in luminescence and relates them to nanoscale chemical inhomogeneities in single InxGa1−xN quantum wells. We demonstrate that the elemental segregation is only inherent to quantum wells with high indium content. Density functional theory shows this to be the result of strain‐induced phase stabilization, explaining ...
Jing‐Yang Chung   +12 more
wiley   +1 more source

JWST Directly Images Giant Planet Candidates Around Two Metal-polluted White Dwarf Stars

open access: yesThe Astrophysical Journal Letters
We report the discovery of two directly imaged, giant planet candidates orbiting the metal-rich, hydrogen atmosphere white dwarfs WD 1202−232 and WD 2105−82. JWST’s Mid-Infrared Instrument (MIRI) data on these two stars show a nearby resolved source at a
Susan E. Mullally   +11 more
doaj   +1 more source

Plaid‐Like Spin Splitting and Chirality of Magnon Bands in Antiferromagnetic MnTe2

open access: yesAdvanced Science, EarlyView.
Helicity‐ and angle‐resolved Raman spectroscopy reveals chiral magnons in the non‐coplanar antiferromagnet MnTe 2. Combined with first‐principles calculations and spin‐wave theory, the results establish its altermagnetic character through circular Raman dichroism, reduced rotational symmetry, and a distinctive plaid‐like momentum‐space magnon spin ...
Dirk Wulferding   +10 more
wiley   +1 more source

Gap‐Free Information Transfer in 4D‐STEM via Fusion of Complementary Scattering Channels

open access: yesAdvanced Science, EarlyView.
Fused Full‐Field STEM (FF‐STEM) is introduced as a 4D‐STEM imaging modality that combines direct ptychography with tilt‐corrected dark‐field reconstruction in a single acquisition. Fourier‐space fusion using Wiener‐type spectral weighting closes the low‐frequency contrast gap inherent to bright‐field methods, delivering gap‐free, dose‐efficient, near ...
Shengbo You   +15 more
wiley   +1 more source

Filter Design for Estimating the Stellar Metallicity of Metal-poor Stars from Gaia XP Spectra

open access: yesThe Astronomical Journal
The estimation of stellar atmospheric parameters for large-scale samples, particularly metal-poor stars, is a cornerstone of Galactic archaeology. In this work, we optimized a photometric filter design tailored to measuring stellar metallicities for very
Ruifeng Shi   +7 more
doaj   +1 more source

PolyG Fibrils Coalesce Into Nuclear Ribbons That Engage Proteostasis Machinery in Neuronal Intranuclear Inclusion Disease

open access: yesAdvanced Science, EarlyView.
In NIID, expanded NOTCH2NLC repeats give rise to nuclear polyG inclusions. Tracer‐guided in situ cryo‐electron tomography enables cross‐scale structural analysis from mouse brain to native neuronal nuclei, revealing dense‐core/peripheral‐halo inclusions built from compact polyG ribbons.
Hui Dong   +13 more
wiley   +1 more source

CORALIE radial-velocity search for companions around evolved stars (CASCADES)

open access: yesAstronomy & Astrophysics
Aims. We extend the planetary census around massive stellar hosts through a long-term campaign of high-precision radial velocity (RV) measurements on evolved stars. Methods.
Figueira P.   +11 more
doaj   +1 more source

Generation and Enhancement of Persistent Nanoscale Magnetization in All‐Dielectric Metasurfaces by Optically Injected and Localized Free Carriers

open access: yesAdvanced Science, EarlyView.
Infrared metasurface‐guided waves (IR‐MGW) scattered by a time interface (TI) induced by rapid, localized free‐carrier generation can be efficiently rectified to generate strong, persistent magnetic fields. We develop a rigorous, theoretical model to study a time‐varying, dispersive medium and uncover the redistribution of the initial energy of the IR ...
Shivaksh Rawat   +2 more
wiley   +1 more source

Magneto-archeology of white dwarfs

open access: yesAstronomy & Astrophysics
The detection of strong, large-scale magnetic fields at the surfaces of the oldest white dwarfs might point toward a hidden internal magnetic field slowly rising to the surface.
Einramhof L.   +4 more
doaj   +1 more source

Evidence for extended chromospheres surrounding red giant stars [PDF]

open access: yes, 1982
Observational evidence and theoretical arguments are summarized which indicate that regions of partially ionized hydrogen extending several stellar radii are an important feature of red giant and supergiant stars.
Stencel, R. E.
core  

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