Photon Factory Activity Report 2004 #22 Part B (2005)
Crystallography

15C/2003G211

Observation of Interference Fringes Induced by Lattice Distortion in Resonant
Scattering X-ray Topography
Riichirou NEGISHI*1, Tomoe FUKAMACHI1, Masami YOSHIZAWA1,Shengming ZHOU2, Takaaki KAWAMURA3
1
Saitama Institute of Technology, 1690 Fusaiji, Okabe, Ohsato, Saitama 369-0293, Japan
2
Shanghai Institute of Optics and Fine Mechanics, 390 Qinghe Road, Jiading, Shanghai, 201800, China
3
University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510, Japan
In the X-ray dynamical diffraction with resonant
scattering, Fourier coefficient χ hi of the imaginary partof X-polarizability can become zero under a certain
condition even in an absorbing crystal. In this condition,
the amplitude of Pendellösung fringe is maximized,
because the electric wave fields of two brunches become
equal to each other at the Bragg angle. In this paper, we
report on the observation of the Pendellösung fringe
induced by lattice distortion in the GaAs 200 reflection
when χ hi = 0 .
The experiment was carried out at BL-15C in KEK-PF.
The X-rays from synchrotron radiation weremonochromated by a Si 111 double-crystal and a GaAs
200 monochromator. The resultant topographic images
are shown in Figs. (1) and (2) which were recorded on thenuclear plate when χ hi = 0 at an X-ray energy of10362eV. The darker contrast corresponds to the higher
X-ray intensity. Fig (1) was the image taken when only Si
111 monochoromator was used, and Fig (2) when both
Si111 and GaAs monochromators were used. The lower
left image in each figure shows the twice magnified
image of the square region. The reciprocal lattice vector his in the upward direction in Fig. (1) and downward in Fig.
(2).
As for the kinematical image of a lattice defect, theintensities of X-rays from the lattice defect area arehigher than those from the perfect area. In addition, therelative distance between two defect images does not*negishi@sit.ac.jp

change with h direction, because the defect sites arereflected directly. In Figs. (1) and (2), the relative
distance from the defect image A to B is the same andboth contrasts of A and B are dark. The defect images A
and B are kinematical ones.
In Fig. (1), the band area in the lower side of A isbright, and that in the upper side is dark. As shown in themagnified image, the interference fringes ofapproximately five lines are observed clearly. The fringe
spacing increases from the lower side to the upper. Theinterference fringe is not observed either in the right orleft of theregion, although the regions show darkcontrasts. In Fig. (2), the corresponding bright-dark
contrasts around A are reversed. The interference fringes
can also be observed in the area marked byand in thearea marked by an arrow D, whose fringe spacing
becomes narrow from the lower side to the upper. Inaddition, some interference fringes are observed within
the zone marked bylocated at the lower side of thedefect image B in Fig. (1), but they are not observed inFig. (2).
In Figs. (1) and (2), the interference fringes areobserved in restricted areas and only in one side of eachimage. This fact implies that the observed interference
fringes are reflected by the lattice distortion. Thus it isnoted that the interference fringe for χ hi = 0 should bequite useful in elucidating the distortion structures.

The topographs for GaAs 200 reflection at X-ray energy equal 10362eV.

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