A general comment about convergence, as there have been a few recent questions.
Convergence is similar to paddling a canoe down a river from the mountains to the sea. Sometimes the water is rushing by and you (the mixer) have to try and avoid the rocks (ghost bands); sometimes you go over a waterfall and the problem changes (electronic phase transition); sometimes you are on a meandering river and do not seem to be making progress. Check-mixing is designed to give some idea about what is going on, as a simple grep on :DIS, for instance, does not reveal enough. _____ Professor Laurence Marks "Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Gyorgi www.numis.northwestern.edu On Tue, Nov 26, 2019, 07:21 Luigi Maduro - TNW <l.a.mad...@tudelft.nl> wrote: > Hello there WIEN2k users, > > > > I am having a convergence problem with a supercell calculation of a slab > of MoS2 including Spin-Orbit Coupling (SOC). The supercell is made by > cutting in the plane of MoS2 which leads to either only edge Mo atoms or > edge S atoms. A vacuum parallel to the edges is introduced (about 18 > angstroms) that separates the repeating images. Converged SCF calculations > without SOC were found with this type of geometry for various widths. These > converged SCF calculations were then used as input for an SCF calculation > with SOC for the different widths. However, when including SOC only the > smallest width gave a converged SCF calculation, albeit after doubling the > amount of k-points and increasing nbands(more than twice what was > originally suggested when running init_so). The larger widths do not result > in a converged SCF calculation, even after substantially increasing nbands. > Is the solution to just keep on increasing the amount of k-points until I > do get converged SCF calculations or is the inclusion of the vacuum giving > problems for lapwso? > > > > > > As a side not, I have a general question on how to relate Emax and nbands > in case.in1. Up until recently I have been using SCALAPACK in WIEN2k and > now I have switched to using ELPA. In the case of MoS2, a system with large > spin-orbit coupling, the userguide recommends to increase the value of Emax > to up to 10 Ry for large SOC systems when running the init_so script. If > one is using ELPA then nbands should be increased. In the case of ELPA > should nbands be increased to twice the amount given in case.in1 when > initially running init_so? > > > > > > PhD candidate > Kavli Institute of Nanoscience > > Department of Quantum Nanoscience > > Faculty of Applied Sciences > > Delft University of Technology > > > _______________________________________________ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > > https://urldefense.proofpoint.com/v2/url?u=http-3A__zeus.theochem.tuwien.ac.at_mailman_listinfo_wien&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=XX2No0AfEa4DjARfeJMqG19OtvlKCdEDrTXWDvLOmqo&s=WGaKK3zLkOCpwqEGHZ8_GDByOyFmnUuDzbYZU5bAppU&e= > SEARCH the MAILING-LIST at: > https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_index.html&d=DwICAg&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=XX2No0AfEa4DjARfeJMqG19OtvlKCdEDrTXWDvLOmqo&s=pdoMtEVvzwPB9V7bLKYqxvdVDi48PKMm7effnVG7774&e= >
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