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 

PhD candidate
Kavli Institute of Nanoscience
Department of Quantum Nanoscience
Faculty of Applied Sciences
Delft University of Technology

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