G. Loupias

Superconductivity of Bulk CaC 6

We have obtained bulk samples of the graphite intercalation compound, CaC6, by a novel method of synthesis from highly oriented pyrolytic graphite. The crystal structure has been completely determined showing that it is the only member of the MC6, metal-graphite compounds that has rhombohedral symmetry. We have clearly shown the occurrence of superconductivity in the bulk sample at 11.5 K, using magnetization measurements.

Electronic density of first stage lithium intercalated graphite

Abstract Electron momentum density of the first stage lithium intercalated graphite, LiC6, has been investigated by X-rays Compton scattering experiments. It is established that the electron given by lithium to carbons is not delocalized but at the same time is different from a graphite Π electron, as expected in the rigid band model.

How the hydrogen bond in NH4F is revealed with Compton scattering

In order to probe electron wave functions involved in the bonding of NH4F, we have performed Compton scattering experiments in an oriented single crystal and in a powder. Ab initio calculations of the Compton profiles for NH4F and NH4Cl are used to enlighten the nature of the bonds in the NH4F crystal. As a consequence, we are able to show significant charge transfer in the ammonium ion which is not observable using other methods. Our study provides a compelling proof for hydrogen bond formation in NH4F.

A study on the Fermi surface of Cr by high-resolution Compton scattering

Abstract A direct Fourier transform method is employed for the first time to reconstruct the electron momentum density projected onto the (110) plane from seven high-resolution Compton profiles. The topological features of the projected Fermi surface obtained by the LCW-folding is compared with the most recent corresponding theoretical results of the all electron charge self-consistent KKR computations.

Theoretical and Experimental Investigation of Electronic Structure of High Pressure Phases of Li Intercalated Graphite

Abstract Electronic structure of a high pressure phase of lithium intercalated graphite has been investigated by theoretical and experimental means. Total energy calculation has shown the existence of a stable phase with LiC2 composition at c=3.38°. A Compton measurement indicates a possible existence of excess Li in the sample.

Phonon dispersion and low-energy anomaly in CaC6 from inelastic neutron and x-ray scattering experiments

We report measurements of phonon dispersion in CaC

Electron Momentum Density Distribution in Cobalt Disilicide: Analysis by the Maximum Entropy Method

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Electron momentum density in Ni75Cu25 and Ni75Co25 disordered alloys: a high-resolution Compton-scattering study

using inelastic X-ray and neutron scattering. We find good overall agreement, particularly in the 50 meV energy region, between experimental data and first-principles density-functional-theory calculations. However, on the longitudinal dispersion along the

Momentum density of electrons in CsRb2C60, versus temperature

(1 1 1)

Momentum density in K4C60 and C60

axis of the rhombohedral representation, we find an unexpected anti-crossing with an additional longitudinal mode, at about 11 meV. At a comparable energy, we observe also unexpected intensity on the in-plane direction. These results resolve the previous incorrect assignment of a longitudinal phonon mode to a transverse mode in the same energy range. By calculating the electron susceptibility from first principles we show that this longitudinal excitation is unlikely to be due to a plasmon and consequently can probably be due to defects or vacancies present in the sample.