Anharmonic Effects on Charge and Orbital Order

Anharmonic effects on charge and orbital order.

Charge and orbital order in Fe3O4.

Charge and orbital ordering in the low-temperature monoclinic structure of magnetite (Fe3O4) is investigated using the local spin density approximation with Coulomb interaction correction method. While the difference between t(2g) minority occupancies of Fe(2+)(B) and Fe(3+)(B) cations is large and gives direct evidence for charge ordering, the screening is so effective that the total 3d charge...

Enhanced stability of charge and orbital order in La0.78Sr2.22Mn2O7

Not only is zigzag charge and orbital ~CO! order shown to be present in the highly doped (x50.61) bilayered manganite system La222xSr112xMn2O7 , it demonstrates an enhanced stability relative to the x 50.5 composition where the ordered state might be expected to have the lowest entropy. No magnetic-field dependence is observed up to 5.25 T. The CO ordering temperature also increases from 210 K ...

Charge order from orbital-dependent coupling evidenced by NbSe2.

Niobium diselenide has long served as a prototype of two-dimensional charge ordering, believed to arise from an instability of the electronic structure analogous to the one-dimensional Peierls mechanism. Despite this, various anomalous properties have recently been identified experimentally, which cannot be explained by Peierls-like weak-coupling theories. Here, we consider instead a model with...

On charge and orbital ordering in La0.5Sr1.5MnO4

Using first principle band structure calculations, we critically examine results of resonant x-ray scattering experiments which is believed to directly probe charge and orbital ordering. Considering the specific case of La0.5Sr1.5MnO4, we show that this technique actually probes most directly and sensitively small structural distortions in the system. Such distortions, often difficult to detect...