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A new family of transition-metal-contg. phosphates ANa3M7(PO4)6, where A = K, Rb, Cs and M = Mn, Fe, Co, was synthesized via high-temp. (650-800°), solid state reactions. Sizable single crystals up to 1 cm (∼160 mg) were grown for structure and property ch ...
The HH and HV Raman spectra of vitreous silica are calculated from first principles for a model structure consisting of a disordered network of corner-sharing tetrahedra, for which the vibrational properties were obtained previously. We analyse the contrib ...
We report x-ray absorption and x-ray linear dichroism measurements at the Fe L-2,L-3 edges of the geometrically frustrated systems of potassium and hydronium iron jarosite. Comparison with simulated spectra, involving ligand-field multiplet calculations mo ...
By using first-principles molecular dynamics within density functional theory, we study the structural properties of amorphous GeSe2 at T = 300 K. The amorphous configurations have been obtained via cooling from the liquid state followed by extensive relax ...
Using a density-functional framework, we investigate the vibrational spectra of vitreous SiO2 to determine to what extent these spectra provide information about the medium-range structure of the oxide network. We carry out a comparative study involving th ...
Inelastic neutron scattering, susceptibility, and high-field magnetization identify LiCuVO4 as a nearest-neighbour ferromagnetic, next-nearest-neighbour frustrated, quasi-one-dimensional helimagnet, which is largely influenced by quantum fluctuations. Comp ...
A model structure of vitreous silica, for which the vibrational frequencies and eigenmodes were calculated from first principles, is used to investigate vibrational amplitudes. Calculated mean-square displacements for oxygen and silicon atoms are obtained ...
Using a first-principles approach, we study the vibrational properties of vitreous SiO2 which are measured in neutron-scattering experiments. We adopt a model structure consisting of corner-sharing tetrahedra, which was previously generated using first-pri ...
In this work, we study two examples of frustrated magnetic systems whose degrees of freedom are spins (or pseudo-spins) on two-dimensional lattices. The first part presents the results obtained for the quantum compass model on a square lattice. This model ...
Using a density-functional approach, we calculate the principal vibrational spectra of vitreous SiO2 and vitreous GeO2 and discuss their analogies and differences. For both glasses, we generate model structures consisting of a random network of corner-shar ...
