2008 NOV 17 - (VerticalNews.com) -- "This article reports the respective photovoltaic processes of singlet and triplet photoexcited states in dissociation and charge reactions based on the studies of magnetic-field effects of photocurrents. The magnetic-field effects of photocurrents reveal that weak donor-acceptor interactions lead to a two-step photovoltaic process: dissociation in polaron-pair states evolved from singlet excitonic states and exciton-charge reactions occurred in triplet excitonic states in the generation of the photocurrent," scientists writing in the journal Advanced Functional Materials report ...read more

  2008 OCT 27 - (VerticalNews.com) -- "The discovery of high-temperature superconductivity in copper oxides was not accidental, but was based on the knowledge that the divalent copper ion, Cu2+, is one of the strongest Jahn-Teller ions," scientists writing in the journal Materials Today report.

  "The Jahn-Teller effect is a consequence of the interplay between electronic degeneracy and coupling to the lattice, i.e. unconventional local electron-lattice interactions. The search for superconductivity in copper oxides was motivated by the idea that Jahn-Teller polaron formation could be a novel and much stronger glue for electron pairing than conventional Bardeen-Cooper-Schrieffer electron-phonon coupling," wrote H. Keller and colleagues, University of Zurich ...read more

  2008 OCT 27 - (VerticalNews.com) -- "The crystal structure of reactive sputtered MnxTi1-xO2 films turns from anatase to rutile as x increases. All the films are ferromagnetic, with a Curie temperature above 340 K. Vacuum annealing enhances the ferromagnetism, of the films, but O-2 annealing weakens it, indicating that the ferromagnetism is related to the oxygen-vacancy defects created by Mn+2 dopants at Ti+4 cations," investigators in Tianjin, People's Republic of China report ...read more