752 research outputs found
Ringtail Disorder observed in Cotton Rats (Sigmodon hispidus)
This is the first description of ringtail syndrome in cotton rats (Sigmodon hispidus). The disorder was sporadically observed in a laboratory reared breeding colony. Incidence of tail lesions decreased after standardization of environmental humidityin the laboratory animal facility
Bandwidth renormalization due to the intersite Coulomb interaction
The theory of correlated electrons is currently moving beyond the
paradigmatic Hubbard , towards the investigation of intersite Coulomb
interactions. Recent investigations have revealed that these interactions are
relevant for the quantitative description of realistic materials. Physically,
intersite interactions are responsible for two rather different effects:
screening and bandwidth renormalization. We use a variational principle to
disentangle the roles of these two processes and study how appropriate the
recently proposed Fock treatment of intersite interactions is in correlated
systems. The magnitude of this effect in graphene is calculated based on cRPA
values of the intersite interaction. We also observe that the most interesting
charge fluctuation phenomena actually occur at elevated temperatures,
substantially higher than studied in previous investigations.Comment: New appendix on benzen
Many-body effects on Cr(001) surfaces: An LDA+DMFT study
The electronic structure of the Cr(001) surface with its sharp resonance at
the Fermi level is a subject of controversial debate of many experimental and
theoretical works. To date, it is unclear whether the origin of this resonance
is an orbital Kondo or an electron-phonon coupling effect. We have combined ab
initio density functional calculations with dynamical mean-field simulations to
calculate the orbitally resolved spectral function of the Cr(001) surface. The
calculated orbital character and shape of the spectrum is in agreement with
data from (inverse) photoemission experiments. We find that dynamic electron
correlations crucially influence the surface electronic structure and lead to a
low energy resonance in the and orbitals. Our results
help to reconvene controversial experimental results from (I)PES and STM
measurements.Comment: 8 pages, 5 figure
- …