Search results for "Fermi–Dirac statistics"
showing 5 items of 5 documents
Temperature dependence of x-ray absorption spectra in the ferromagnetic Heusler alloysMn2VAlandCo2FeAl
2010
We investigate the temperature dependence of the spin-resolved unoccupied density of states (DOS) in ferromagnetic ${\text{Co}}_{2}\text{FeAl}$ and ferrimagnetic ${\text{Mn}}_{2}\text{VAl}$ epitaxial films on MgO(100) using x-ray magnetic circular dichroism. We observe an unexpected strong temperature dependence of the DOS beyond the change expected from the Fermi distribution function. An increase in spectral weight is observed for majority states below the Fermi energy in the case of ${\text{Mn}}_{2}\text{VAl}$ and for minority states above the Fermi energy in the case of ${\text{Co}}_{2}\text{FeAl}$. Reduced atomic order near the interface suppresses the unexpected temperature dependence…
Fermi-Dirac correlations in Lambda pairs in hadronic Z decays
2000
Two-particle correlations of Lambda Lambda and pairs have been studied in multihadronic Z decays recorded with the ALEPH detector at LEP in the years from 1992 to 1995. The correlations were measured as a function of the four-momentum difference Q of the pair. A depletion of events is observed in the region Q 2 GeV the fraction of pairs with spin one is consistent with the value of 0.75 expected for a statistical spin mixture, whilst for Q pairs, where no Fermi-Dirac correlations are expected, the spin one fraction is measured to be consistent with 0.75 over the entire analysed Q range. (C) 2000 Elsevier Science B.V. All rights reserved.
Temperature dependence of the effective mobility edge and recombination dynamics of free and localized excitons in InGaP/GaAs quantum wells
2003
3 páginas, 1 figura.-- Comunicación presentada al Proceedings of the International Conference on Superlattices, Nano-structures and Nano-devices ICSNN 2002 o-structures and Nano-devices ICSNN 2002.
Accurate Evaluation of Fermi-Dirac Integrals and Their Derivatives for Arbitrary Degeneracy and Relativity
1996
The equation of state of an ideal Fermi gas is expressed in terms of Fermi-Dirac integrals. We give formulae for evaluation the Fermi-Dirac integrals of orders 1/2, 3/2, and 5/2 and their derivatives in various limits of non- and extreme degeneracy and relativity. We provide tables and a Fortran subroutine for numerical evaluation of the integrals and derivatives when a limit does not apply. The functions can be evaluated to better than 1% accuracy for any temperature and density using these methods.
Dependence of atomic parity-violation effects on neutron skins and new physics
2019
We estimate the relative contribution of nuclear structure and new physics couplings to the parity non-conserving spin-independent effects in atomic systems, for both single isotopes and isotopic ratios. General expressions are presented to assess the sensitivity of isotopic ratios to neutron skins and to couplings beyond standard model at tree level. The specific coefficients for these contributions are calculated assuming Fermi distribution for proton and neutron nuclear densities for isotopes of Cs, Ba, Sm, Dy, Yb, Pb, Fr, and Ra. The present work aims to provide a guide to the choice of the best isotopes and pairs of isotopes for conducting atomic PNC measurements.