Would you please have a look at the images attached and clarify whether there are any twins in the images or they are just Miore fringes.
I indexed the corresponding FFT of the image and found the twin plane of (121), the common twin plane for bcc materials (my material is bcc Ti). However, a reviewer questioned these results and mentioned that the different lattice planes come from the same crystalline lattice.
He can be right, but if there is no twin and all the strip contrasts are from the same lattice why FFT shows a diffraction pattern for twins?
Thanks in advance for helping.
Cheers,
Ahmad
Hi Zafari, I would think the region you worked on has two overlapping crystals. So the result you get is Moire fringes.
Have you done any tilting on the same region?
I think this is a small angle boundary of two crystals overlapping in beam direction. They simply lay on top of each other and cause a double diffraction effect. The split between the first satellite dots to the central beam gives the value for the rotation angle.
Thanks everyone for your time and helpful comments. Yes, I do agree now that what I got were Moire fringes. I could remove fringes by modifying the image using digital filtering.
We observed something similar in the van der Waals epitaxy of WS2 on MoTe2. We expected the LEED patterns as a Moire, but in the I-V analysis it turned out that the layers are undulated in addition. So the Moire was superposed by the diffraction from an undulated overlayer.
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