Dear all
Recently, I am trying to calculate the phonon dispersion of 2D materials. I used 4x4x1 q-points in phonon calculation whereas a 16x16x1 k-points for self-consistent electronic calculation. The direct calculations indicate that all phonons frequencies are above zero on the grid of q-vectors including the Gamma point. However, when I transformed the dynamical matrices from G- to R-space and calculated phonon dispersions using ?matdyn.x?, some negative frequencies appear in acoustic mode ZA near Gamma point. Since I am really a new user for phonon calculation, I am not sure what happened. The input and output file are enclosed. Could you tell me what?s wrong with my calculations? Any suggestions will be appreciated. Thanks and best regards Wei-Bing Zhang ---------------------------------------------------------------------- Dr. Wei-Bing Zhang School of Physics and Electronic Sciences Changsha University of Science and Technology, Changsha, People?s Republic of China Phone : +86 186 73108538 E-mail: zwb256 at hotmail.com, weibingzhangavh at gmail.com ---------------------------------------------------------------------- -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20130618/0a05c0b3/attachment.html -------------- next part -------------- A non-text attachment was scrubbed... Name: test2.tar.gz Type: application/octet-stream Size: 69544 bytes Desc: not available Url : http://pwscf.org/pipermail/pw_forum/attachments/20130618/0a05c0b3/attachment.obj
