By resonant x-ray scattering at the Mn K edge on La(7/8)Sr(1/8)MnO3, we show that an orbital polaron lattice (OPL) develops at the metal-insulator transition of this compound. This orbital reordering explains consistently the unexpected coexistence of ferromagnetic and insulating properties at low temperatures, the quadrupling of the lattice structure parallel to the MnO2 planes, and the observed polarization and azimuthal dependencies. The OPL is a clear manifestation of strong orbital-hole interactions, which play a crucial role for the colossal magnetoresistance effect and the doped manganites in general.
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http://dx.doi.org/10.1103/PhysRevLett.95.236401 | DOI Listing |
J Chem Theory Comput
November 2024
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States.
Doped conjugated polymers have a variety of potential applications in thermoelectric and other electronic devices, but the nature of their electronic structure is still not well understood. In this work, we use time-dependent density functional theory (TD-DFT) calculations along with natural transition orbital (NTO) analysis to understand electronic structures of both p-type (e.g.
View Article and Find Full Text PDFNanoscale Horiz
December 2024
Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Composite quasi-particles with emergent functionalities in spintronic and quantum information science can be realized in correlated materials due to entangled charge, spin, orbital, and lattice degrees of freedom. Here we show that by reducing the lateral dimension of correlated antiferromagnet NiPS flakes to tens of nanometers and thickness to less than ten nanometers, we can switch-off the bulk spin-orbit entangled exciton in the near-infrared (1.47 eV) and activate visible-range (1.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, No.1, Xikang road, Nanjing 210098, China.
In a photocatalysis process, quick charge recombination induced by small electron polarons in a photocatalyst and sluggish kinetics of hole transfer at the solid-liquid interface have greatly limited photocatalytic efficiency. Herein, we demonstrate hydrated transition metal ions as mediators that can simultaneously accelerate small electron polaron dissociation (via metal ion reduction) and hole transfer (through high-valence metal production) at the solid-liquid interface for improved photocatalytic pollutant degradation. Fe, by virtue of its excellent redox ability as a homogeneous mediator, enables the BiVO photocatalyst to achieve drastically increased photocatalytic degradation performance, up to 684 times that without Fe.
View Article and Find Full Text PDFPhys Rev Lett
October 2024
Instituto de Nanociencia y Nanotecnología CNEA-CONICET, Centro Atómico Bariloche and Instituto Balseiro, 8400 Bariloche, Argentina.
We develop a theory that explains the low-energy optical excitations near 1.5 eV observed by optical experiments in NiPS_{3}. Using ab initio methods, we construct a two-band Hubbard model for two effective Ni orbitals.
View Article and Find Full Text PDFNat Commun
September 2024
Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
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