# SPring-8, the large synchrotron radiation facility

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SOL-0000001159

## Beamline

BL08W (High Energy Inelastic Scattering)

## Scientific keywords

A. Sample category inorganic material metal, alloy, superconductor, magnetic material, solid-state crystal inelastic scattering Compton scattering polarization (linear), room temperature X-ray (> 40 keV) electronic state

## Industrial keywords

level 1---Application area storage device HD,MO electronic state X-ray diffraction

## Classification

A80.12 semiconductor, A80.14 magnetic materials

## Body text

Compton scattering measurement is a efficient technique to study electron momentum density distribution. Using this technique, one can measure electronic structure such as the Fermi surface geometry or the number of electrons in each orbital states. This technique is executable in various experimental conditions because of its insensibility to crystalline imperfections and its applicability to bulky samples. The figure shows the 2D electron momentum density using reconstruction method. It experimentally determined the two-dimensional electron momentum density of Sr2RuO4.

Two-dimensional momentum density of Sr2RuO4, reconstructed from five directional Compton profiles.

Beamline Report

35

## Technique

Compton profile; J(pz) corresponds to the energy spectrum of Compton scattered X-rays on  fixed angle. It directly provides a twice integrated electron momentum density. The area under the Compton profile is equal to the number of total electrons. Compton Profile can be decomposed into a few partial profiles with the characteristic shape of a specific electronic state, the area under the partial profile gives the number of electrons associated with that state. 2D/3D electron momentum density can be obtained using the reconstruction method from several number of Compton profiles.

$J(p_z) = \iint \rho (\b{p}) dp_xdp_y$

No figure

4 hour(s)

## Instruments

Instrument Purpose Performance
High resolution Compton scattering spectrometer Compton measurement momentum resolution 0.14 atomic unit

## References

Document name
N. Hiraoka, et.al., Physical Review B, 67 (2003) 94511

## Related experimental techniques

angle-resolved photoelectronemission spectroscopy
positron annihilation
electron scattering

## Questionnaire

The measurement was possible only in SPring-8. Impossible or very difficult in other facilities.
This solution is an application of a main instrument of the beamline.
Similar experiments account for more than 30% of the beamline's subject.

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### How many shifts were needed for taking whole data in the figure?

More than ten shifts