Hi everyone,
My query might look silly but I am new to VASP. I am trying to reproduce few results for learning purpose. I took a two dimensional MoSSe sheet. I have added a sulfur defect in the relaxed MoSSe sheet and relax it again by taking INCAR:
ISTART = 0
ICHARG = 2
ENCUT = 450
IBRION = 1
EDIFF = 0.00000001
EDIFFG = -0.0001
NSW = 100
ISIF = 2
ISMEAR = 0 ; SIGMA = 0.05
LREAL = Auto
Although I got converged geometry but few of the bonds got broken.
But in reported articles the pristine sheet (pure sheet) and defected sheet look exactly same except the defect.
Please let me know if I am doing something wrong in the input file.
Thanks in advance.
Dear Kaur：
it seems you misunderstand the basic concept of bond in condense matter. Sure the bond is kind of relative to the atoms distance, but many visualization software just simplely judge specific two atoms forming a bond while the atom distance was within a default cutoff. Different sofware have diffenrent default values. Anyhow, bond is really a big and fuzzy concept in condense matter, i recommend to read the How Chemistry and Physics Meet in the Solid State wirtten by Hoffman.By the way, you do not need to set EDIFFG ti such a small value. -0.01 is olkay anyway. As a two dimensional covalent crystal, you must consider the van der Walss into calculation . see IVDW in VASP turiol. DFT-D3 is enough.
Dear Chunjin Chen,
Thank you very much for your kind reply. Yes, you are correct that the cut off value of bonds between atoms is different in different visualizing software. In my case, the pristine and doped structures are looking bit different after relaxation. I have attached the images of both pristine as well as doped MoSSe sheet herewith.
Please help me to figure out where am I doing wrong? why in VESTA, few of the atoms are missing after relaxation in the case of doped 2D sheet?
Thanks in advance
Surinder
Dear Kayr：
I have seen your two images. i think this difference between these two images are resulkting from the periodicty. You can just make a 2x2 supercell to have a good look. Besides, some diffrent parameters will infuluence the specific distorsion around impurity, but this have nothing to do with your final results. I think your result matches well with paper, just periodicity troubled you.
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