59,028 research outputs found
Itinerant magnetism in metallic CuFe2Ge2
Theoretical calculations are performed to understand the electronic structure
and magnetic properties of CuFeGe. The band structure reveal large
electron density at the Fermi level suggesting strong itinerant
character of magnetism. The Fermi surface is dominated by two dimensional sheet
like structures, with potentially strong nesting between them. The magnetic
ground state appears to be ferromagnetic along and antiferromagnetic in
other directions. The results show that CuFeGe is an antiferromagnetic
metal, with similarities to the Fe-based superconductors; such as magnetism
with substantial itinerant character and coupling between magnetic order and
electrons at the Fermi energy.Comment: 5 pages, 6 figure
Tables of X-coefficients and Lambda-factors for Triple Angular Correlation Analysis
Tables of x-coefficients and lambda-factors for triple angular correlation measurements in nuclear reaction studie
Spin waves in the (0,pi) and (0,pi,pi) ordered SDW states of the t-t' Hubbard model: Application to doped iron pnictides
Spin waves in (0,pi) and (0,pi,pi) ordered spin-density-wave (SDW) states of
the t-t' Hubbard model are investigated at finite doping. In the presence of
small t', these composite ferro-antiferromagnetic (F-AF) states are found to be
strongly stabilized at finite hole doping due to enhanced carrier-induced
ferromagnetic spin couplings as in metallic ferromagnets. Anisotropic spin-wave
velocities, spin-wave energy scale of around 200meV, reduced magnetic moment,
and rapid suppression of magnetic order with electron doping x (corresponding
to F substitution of O atoms in La O_{1-x} F_x Fe As or Ni substitution of Fe
atoms in Ba Fe_{2-x} Ni_x As_2) obtained in this model are in agreement with
observed magnetic properties of doped iron pnictides.Comment: 13 pages, 3 figure
Electronic Structure and Thermoelectric Prospects of Phosphide Skutterudites
The prospects for high thermoelectric performance in phosphide skutterudites
are investigated based on first principles calculations. We find that
stoichiometric CoP_3 differs from the corresponding arsenide and antimonide in
that it is metallic. As such the band structure must be modified if high
thermopowers are to be achieved. In analogy to the antimonides it is expected
that this may be done by filling with La. Calculations for LaFe_4P_12 show that
a gap can in fact be opened by La filling, but that the valence band is too
light to yield reasonable p-type thermopowers at appropriate carrier densities;
n-type La filled material may be more favorable.Comment: 3 pages, 3 figures, 1 tabl
Cohesion of BaReH and BaMnH: Density Functional Calculations and Prediction of (MnH Salts
Density functional calculations are used to calculate the structural and
electronic properties of BaReH and to analyze the bonding in this compound.
The high coordination in BaReH is due to bonding between Re 5 states and
states of -like symmetry formed from combinations of H orbitals in the
H cage. This explains the structure of the material, its short bond lengths
and other physical properties, such as the high band gap. We compare with
results for hypothetical BaMnH, which we find to have similar bonding and
cohesion to the Re compound. This suggests that it may be possible to
synthesize (MnH salts. Depending on the particular cation, such salts
may have exceptionally high hydrogen contents, in excess of 10 weight
Neutrino Induced Charged Current 1 Production At Intermediate Energies
The charged current one pion production induced by from nucleons
and nuclei like C and O nuclei has been studied. The calculations
have been done for the incoherent and the coherent processes from nuclear
targets assuming the dominance model and take into account the effect
of Pauli blocking, Fermi motion of the nucleon and renormalization of
properties in a nuclear medium. The effect of final state interactions of pions
has been taken into account. The theoretical uncertainty in the total cross
sections due to various parameterizations of the weak transition form factors
used in literature has been studied. The numerical results for the total cross
sections are compared with the recent preliminary results from the MiniBooNE
collaboration on C and could be useful in analyzing future data from the
K2K collaboration.Comment: 10 pages, 6 figures, 1 tabl
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