Dear all
I am constructing a multilattice system, say, (ZnO)1-x(GaN)x where the Ga and N substitute Zn and O, respectively. In addition, the composition of Ga and N in the alloy system should be Ga : N = 1:1. Can someone give me some tips how to set the constraint Ga : N = 1:1 in the mmaps input file?
The lat.in file i set is as follows
3.2682035210 0.000000000000 0.00000000000
-1.634101760 2.830347273924 0.00000000000
0.0000000000 0.000000000000 5.29497595200
1.0000000000 0.000000000000 0.00000000000
0.0000000000 1.000000000000 0.00000000000
0.0000000000 0.000000000000 1.00000000000
0.6666666666666714 0.3333333333333286 0.0000000000000000 Zn, Ga
0.3333333333333286 0.6666666666666714 0.5000000000000000 Zn, Ga
0.6666666666666714 0.3333333333333286 0.3805652713655142 O, N
0.3333333333333286 0.6666666666666714 0.8805652713655142 O, N
Thank you
cheers
Maofeng
The input file for mmaps should be the same as the mcsqs generator, so let me see if I can help.
Firstly, if this input file is the unit cell, then you’ll need to know what x is. It should follow the following:
Zn = y atoms
Ga = z atoms
Zn=(z)/(y+z), Ga=z/(y+z)
and likewise for the other type. The idea is when your decimal is multiplied by the number of atoms in your supercell, they should all be integers that add up to x.
Hopefully, that helps. (Maybe not, as I haven’t used mmaps yet)
Thanks a lot Forrest.
I have tried change the input format the same as MCSQS (example shown below), unfortunately, did not work. As I understood, the concentration in MMAPS should be controlled by CRANGE.IN file instead of lat.in (maybe I am wrong, I started to use ATAT few days ago).
Example of Lat.in suggested by Forrests (unit cell here)
3.2682035210 0.000000000000 0.00000000000
-1.634101760 2.830347273924 0.00000000000
0.0000000000 0.000000000000 5.29497595200
1.0000000000 0.000000000000 0.00000000000
0.0000000000 1.000000000000 0.00000000000
0.0000000000 0.000000000000 1.00000000000
0.6666666666666714 0.3333333333333286 0.0000000000000000 Zn=0.75,Ga=0.25
0.3333333333333286 0.6666666666666714 0.5000000000000000 Zn=0.75,Ga=0.25
0.6666666666666714 0.3333333333333286 0.3805652713655142 O=0.75,N=0.25
0.3333333333333286 0.6666666666666714 0.8805652713655142 O=0.75,N=0.25
Can we understood the problem in this way: substituting Zn-O pair with Ga-N pair, which kind like grouping the Zn-O sites together. if so, can we control it through the following constraints?
1Ga-1N<=0.1
1Ga-1N>=-0.1
Thanks
Maofeng
Okay, so I took a look at mmaps in the manual, it seems you have too. In my brief understanding of it, your original input file is correct. You simply must tell it which clusters to include in the expansion. To determine the ratios, you are right, you need to edit CRANGE.in .
If you can try this for CRANGE.in (or any other numbers keeping 0.1 and 0.5 consistent)
1Zn - 1Ga>=0.1
1O - 1N >=0.1
1Zn - 1Ga<=0.5
1O - 1N <=0.5
I’m not entirely sure if the <= works as I haven’t read through the paper on this with potential examples. From what I understand this is the range of concentrations you want, so if 1-y >=.1 . You might be able to just specify a single concentration with an equal sign. I don’t think a negative concentration makes sense, but of course you can try that.
Wish I could help more, in any case, if it doesn’t and you need someone to bounce ideas off of, I’ll be here.
Dear Forrest
Thanks for detailed and valuable suggestions. After changed the constraints in CRANGE.IN (both yours and Axel’s suggestion are reasonable), the structure generation works smoothly. I just found today that the similar problems actually already answered by Axel before (see link below). Sorry for not reading the topics carefully before posting.
The only problem I meet now is the mmaps stays on status "Finding best structures … "for long time (more than 1h) after generating 4 structures. I may need to think about the structure and constraints carefully.
The constraints I am using now is
1.0Ga -1.0N <= 0.05
1.0Ga -1.0N >= -0.05
1.0Zn -1.0O <= 0.05
1.0Zn -1.0O >= -0.05
Cheers
Maofeng
Mind if I ask why the negative concentration works?
I think you may use the charge banlance limit instead.
3Ga+2Zn-3N-2O<=0.1
3Ga+2Zn-3N-2O>=-0.1