In most of the atomistic simulations, symmetric (asymmetric) tilt grain boundaries are studied. Is there any relationship with the GBs in the real world.
That is an interesting question. I will try to answer with respect to my own field of research, that is 2D materials.
As far as I know, tilt GBs are mainly considered over twist GBs for a practical reason. Experimentally observed GBs in 2D materials depends on the method one uses to grow the flakes. This is typically done by CVD. For 2D materials, the many seeds present are randomly oriented and therefore it will lead to grain growing with different orientations. This means that most GBs will accommodate for the lattice mismatch and the orientation mismatch. However, twist boundaries were also studied for 2D materials as they exhibit extremely interesting properties.
In conclusion, tilt or twist don't matter if you're considering atomistic simulations. The number of atoms to describe your system is the main criterion, which often strongly depends on the symmetry or asymmetry of the GB. Besides, it also depends if you're trying to describe experimentally observed GBs or more exotic ones that have interesting properties.
Best
Could you clarify your question ?
If your question is as I guess : "why most of the atomic studies are done on symmetric GBs ?". Then the answer is that symmetric ones contain in general less atoms per unit cell than asymmetric ones (A noteworthy exception is the (5,0)|(3,3) GB). With tools such as DFT, it is a crucial point that determines if the calculation is feasible or not.
Best,
S. Dechamps
You can do Twist Grain Boundaries as well but their structures are more complicated to create as compared to Symmetric (Asymmetric) Tilt Grain Boundaries for MD simulations. The tilt and twist boundaries represent somewhat idealized cases as majority of boundaries are of a mixed type, containing dislocations of different types and Burgers vectors. But owing to the structural complexity and limited information about mixed grain boundaries it is very difficult create them for MD simulations.
Mr. Samuel Dechamps ,
Yes, my question was 'why most of the atomic studies were done on symmetric tilt GBs ?'.
Thanks for your answer. I like to add to the point that, why tilt GBs are considered and not much of twist or mixed GBs in general are studied with atomistic techniques.
That is an interesting question. I will try to answer with respect to my own field of research, that is 2D materials.
As far as I know, tilt GBs are mainly considered over twist GBs for a practical reason. Experimentally observed GBs in 2D materials depends on the method one uses to grow the flakes. This is typically done by CVD. For 2D materials, the many seeds present are randomly oriented and therefore it will lead to grain growing with different orientations. This means that most GBs will accommodate for the lattice mismatch and the orientation mismatch. However, twist boundaries were also studied for 2D materials as they exhibit extremely interesting properties.
In conclusion, tilt or twist don't matter if you're considering atomistic simulations. The number of atoms to describe your system is the main criterion, which often strongly depends on the symmetry or asymmetry of the GB. Besides, it also depends if you're trying to describe experimentally observed GBs or more exotic ones that have interesting properties.
Best
Mr. Pulkit Garg
Thanks for your answer. It is surprising to see lot of research articles coming up with simulations and results of Tilt GBs even it is an ideal case in grain boundary engineering.
But few GBs like Sigma 3 twin boundaries and low angle GBs modeled through symmetric tilt method can be correlated to experimental or real world GBs.
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