Dear PWscf developers and users, I am currently studying an epitaxial thin-film system. I would like to find the optimized the structure with the lattice parameters a and b being constrained, namely, finding the optimized lattice parameter c (and the internal structure).
I am aware that this procedure can be done manually. But that would cost lots of CPU hours. I am considering using cell_dofree, and I am wondering how this option works. Suppose I put cell_dofree= 'z' under the namelist &CELL. How should I specify the target pressure? For a thin film with constrained a, b and optimized c, the stress tensor should look like sigma_xx = sigma_yy = a non-vanishing value. sigma_xy = sigma_yx = also a non-vanishing value sigma_zz = sigma_xz = sigma_yz = 0 But when specifying press= 0, I think (maybe I am wrong) the program is searching for a structure with sigma_ij=0, i,j=x,y,z. How should I specify the target pressure (stress tensor) if I perform vc-relax with dofree= 'z'? Thank you in advance for your response and hint. Han -- ************************************************************************* Han Hsu, Ph.D. Postdoctoral Associate Department of Chemical Engineering & Materials Science University of Minnesota http://www.cems.umn.edu/~hsuhan <http://www.cems.umn.edu/%7Ehsuhan> ************************************************************************* -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20100819/129d3562/attachment-0001.htm
