1,025 research outputs found
GW correlation effects on plutonium quasiparticle energies: changes in crystal-field splitting
We present results for the electronic structure of plutonium by using a
recently developed quasiparticle self-consistent method (\qsgw). We
consider a paramagnetic solution without spin-orbit interaction as a function
of volume for the face-centered cubic (fcc) unit cell. We span unit-cell
volumes ranging from 10% greater than the equilibrium volume of the
phase to 90 % of the equivalent for the phase of Pu. The
self-consistent quasiparticle energies are compared to those obtained
within the Local Density Approximation (LDA). The goal of the calculations is
to understand systematic trends in the effects of electronic correlations on
the quasiparticle energy bands of Pu as a function of the localization of the
orbitals. We show that correlation effects narrow the bands in two
significantly different ways. Besides the expected narrowing of individual
bands (flatter dispersion), we find that an even more significant effect on the
bands is a decrease in the crystal-field splitting of the different bands.Comment: 9 pages, 7 figures, 3 table
The Electronic Correlation Strength of Pu
An electronic quantity, the correlation strength, is defined as a necessary
step for understanding the properties and trends in strongly correlated
electronic materials. As a test case, this is applied to the different phases
of elemental Pu. Within the GW approximation we have surprisingly found a
"universal" scaling relationship, where the f-electron bandwidth reduction due
to correlation effects is shown to depend only on the local density
approximation bandwidth and is otherwise independent of crystal structure and
lattice constant.Comment: 7 pages, 4 figures, This version of the paper has been revised to add
additional background informatio
Ab initio LSDA and LSDA+U study of pure and Cd-doped cubic lanthanide sesquioxides
The electronic, structural, and hyperfine properties of pure and Cd-doped lanthanide (Ln) sesquioxides with the cubic bixbyite structure (Ln2O3, Ln ranging from La to Lu) have been studied using the full-potential augmented plane wave plus local orbital (APW + lo) method within the local spin density approximation (LSDA) and the Coulomb-corrected LSDA + U. In the case of the pure systems, our calculations show that LSDA + U gives a better representation of the band structure compared to LSDA. The predicted equilibrium structures and the electric field gradient (EFG) tensor at Ln sites were calculated and compared with those obtained by means of hyperfine techniques and with theoretical results obtained in In2O3, Sc2O3, and Lu2O3 reported in the literature. The origin of the EFG at Ln sites and the role played by the 4f electrons on this quantity are discussed. In the case of the Cd-doped systems, the APW + lo method (also within LSDA and LSDA + U) was applied to treat the electronic structure of the doped system. The role of the Ln 4f electrons on the EFG at Cd impurity sites, and other variables like structural distortions induced by the Cd impurity, were investigated in detail and are discussed and compared with available experimental results. An excellent agreement between the experimental and calculated EFGs was found for all Cd-doped systems.Fil: Richard, Diego. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de FĂsica; ArgentinaFil: Muñoz, Emiliano Luis. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de FĂsica; ArgentinaFil: RenterĂa, Mario. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de FĂsica; ArgentinaFil: Errico, Leonardo Antonio. Universidad Nacional del Noroeste de la Provincia de Buenos Aires; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de FĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂsica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de FĂsica; ArgentinaFil: Svane, A.. University Aarhus. Institut for Fysik Og Astronomi; DinamarcaFil: Christensen, N. E.. University Aarhus. Institut for Fysik Og Astronomi; Dinamarc
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