I use wide-spread ribbon model for MoS2 edge. To ensure correctness of the model I calculated supercells with 2,3,4,6 periods (Mo atoms) along the edge. I expected that at least for one row of 2-4-6 or 3-6 I would see constant specific energy per edge Mo atom.
Instead I see a slight, but constant increase in specific energy. The increase is small (~0.2 eV/period) but constant. It was observed for series with 2k points for all supercell sizes and for series where I used such number of K-point that product of supercell size and number of k-points were preserved. I could dismiss it, but ! That increase is observed for some structures in same model and not observed for others. If the increase was uniform between structures, I could dismiss it. As of now I need to understand where it comes from. What I should see for in my results and what could be the reason? Interestingly, when I run same calculation with Gamma-point, I saw different pattern, but this is of no importance now. _______________________________________________ users mailing list users@lists.quantum-espresso.org https://lists.quantum-espresso.org/mailman/listinfo/users