Simulation of Si3N4

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1

Hi Prof. Kohlmeyer,

I got your point and my apology for failing to elaborate appropriately on the problem. For potential, I used tersoff potential which was calibrated by Brito Mota. For the initial configuration, I downloaded the .Cif file of Beta silicon nitride from crystallography.net and also I built it using the space group and then I replicated it to obtain a thin layer ( ending in the same results for both cases ). For stress, I used virial and for strain, it is engineering strain. I attached my files ( Si3N4. in as my initial configuration and Input.in as my input command SiN as the parameters of tersoff potential). I also, attach the diagram I expect to get based on a published paper [1]. But, anyway the answer I get is not correct as I obtain a high value of fracture stress and even strain. I will deeply appreciate your help within any comment. Honestly, this is the problem that I’m working on it for a month. But, unfortunately I couldn’t solve it and I really think that to the best of my knowledge I’m doing the simulation correctly.

Eagerly looking forward to hear back from you,

Kind regards,

Ali

[1] http://pubs.acs.org/doi/abs/10.1021/jz4007977

Stress - Strain.PNG

Stress - Strain ( Paper ).PNG

Input files.rar (48 KB)

2

you seem to be deforming in z direction, yet your system is extremely shallow in z. i would suggest to check, if your result is dependent on the thickness of your system in z.

axel.

3

You could check structural properties (density, bond length, angle) of the equilibrated system before tensile simulation to make sure Tersoff is working well in your case.

Sanjib