Dear developers, I study flexoelectric effect which can be seen as a repulsion of TA and TO branches in the vicinity of gamma point. I calculate phonon dispersion of cubic SrTiO3. It's essential for me to have adequate picture of phonons in the vicinity of gamma point (at least for q>0.05).
The picture shows TA and TO branches single q-point (st.ph.single.in) calculations (grey dots) and dispersion (st.ph.disp.in) for 8x8x8 mesh. [cid:image003.png at 01CFBBD0.39A26750] With used parameters ph.x fails to give right values for small values of q-vector. I guess it's due to numerical errors of the code. What are the main reasons for this numerical error when we go close to gamma point. Which parameters should I adjust to improve the situation? Attached, all relevant inputs and outputs Sincerely yours, Alexander Kvasov Ceramics Laboratory / THEOS (Theory and Simulation of Materials) Laboratory ?cole Polytechnique F?d?rale de Lausanne (EPFL) Phone: +41 21 693 5805 Address: EPFL STI IMX LC MXD 220 (B?timent MXD) Station 12 1015 Lausanne, Switzerland -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20140819/0ffb810c/attachment.html -------------- next part -------------- A non-text attachment was scrubbed... Name: image003.png Type: image/png Size: 34712 bytes Desc: image003.png Url : http://pwscf.org/pipermail/pw_forum/attachments/20140819/0ffb810c/attachment.png -------------- next part -------------- A non-text attachment was scrubbed... Name: st.in Type: application/octet-stream Size: 1206 bytes Desc: st.in Url : http://pwscf.org/pipermail/pw_forum/attachments/20140819/0ffb810c/attachment.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: st.out Type: application/octet-stream Size: 16162 bytes Desc: st.out Url : http://pwscf.org/pipermail/pw_forum/attachments/20140819/0ffb810c/attachment-0001.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: st.ph.disp.in Type: application/octet-stream Size: 589 bytes Desc: st.ph.disp.in Url : http://pwscf.org/pipermail/pw_forum/attachments/20140819/0ffb810c/attachment-0002.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: st.ph.single.in Type: application/octet-stream Size: 544 bytes Desc: st.ph.single.in Url : http://pwscf.org/pipermail/pw_forum/attachments/20140819/0ffb810c/attachment-0003.obj
