19,813 research outputs found
How chromium doping affects the correlated electronic structure of V2O3
The archetypical strongly correlated Mott-phenomena compound V2O3 is known to
show a paramagnetic metal-insulator transition driven by doping with chromium
atoms and/or (negative) pressure. Via charge self-consistent density-functional
theory+dynamical mean-field theory calculations we demonstrate that these two
routes cannot be understood as equivalent. To this end, the explicit
description of Cr-doped V2O3 by means of supercell calculations and the virtual
crystal approximation is performed. Already the sole introduction of chromium's
additional electron to the system is shown to modify the overall correlated
electronic structure substantially. Correlation-induced charge transfers
between Cr and the remaining V ions occur and the transition-metal orbital
polarization is increased by the electron doping, in close agreement with
experimental findings.Comment: 6 pages, 8 figure
Neural Network Modeling of Sensory-Motor Control in Animals
National Science Foundation (IRI 90-24877, IRI 87-16960); Air Force Office of Scientific Research (F49620-92-J-0499); Office of Naval Research (N00014-92-J-1309
CBBN in the CMSSM
Catalyzed big bang nucleosynthesis (CBBN) can lead to an overproduction of
^6Li in gravitino dark matter scenarios in which the lighter stau is the
lightest Standard Model superpartner. Based on a treatment using the
state-of-the-art result for the catalyzed ^6Li production cross section, we
update the resulting constraint within the framework of the constrained minimal
supersymmetric Standard Model (CMSSM). We confront our numerical findings with
recently derived conservative limits on the gaugino mass parameter and the
reheating temperature.Comment: 4 pages, 4 figures; Submitted for the SUSY07 proceeding
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