ABINIT Discussion Forums

Dear professors,
I give the parameters of conventional cell of Sr2VO4 (from VESTA) in the Input file:
acell 7.24385633 7.24385633 23.7996219
rprim 1.0 0.0 0.0
0.0 1.0 0.0
0.0 0.0 1.0
ntypat 3
znucl 8 23 38
natom 14
typat 1 1 1 1 1 1 1 1 2 2 3 3 3 3
xred
0.500000000 0.000000000 0.000000000
0.000000000 0.500000000 0.000000000
0.000000000 0.500000000 0.500000000
0.500000000 0.000000000 0.500000000
0.000000000 0.000000000 0.157810000
0.000000000 0.000000000 0.842190000
0.500000000 0.500000000 0.657810000
0.500000000 0.500000000 0.342190000
0.000000000 0.000000000 0.000000000
0.500000000 0.500000000 0.500000000
0.500000000 0.500000000 0.144860000
0.500000000 0.500000000 0.855140000
0.000000000 0.000000000 0.644860000
0.000000000 0.000000000 0.355140000
we know that spgroup of Sr2VO4 shoud be 139, but I get 123 from the out file.
I have tried my best to find the reason, but failed.Would you kindly tell me why?
I have tested my .cif by http://stokes.byu.edu/iso/findsym.php

Doing the symmetry analysis with any symmetry tool (findsym, ....) gives I4mmm.
You can try abinit with changing tolsym to something larger than the default value which is quite small.
Their must be one digit that is wrong when running abinit that breaks symmetries.

Cheers

Jordan wrote:Doing the symmetry analysis with any symmetry tool (findsym, ....) gives I4mmm.
You can try abinit with changing tolsym to something larger than the default value which is quite small.
Their must be one digit that is wrong when running abinit that breaks symmetries.

Cheers

Thanks for you answers!
I have tried to set tolsym to be 1e-3, but I get the same answer. You know, I want to construct a conventional cell, so I copy the structure parameters from POSCAR of VASP.
Here I consider the system Sr2VO4 to be AFM, the out file tells me the symmetry message
"Magnetic group, Shubnikov type IV
Fedorov space group P4/m m m (#123)
Magnetic Bravais lattice tP_I (primitive tetrag., centered magnetic, #25)"
If I quit the spin polarization, it tells me "Symmetries : the unit cell is not primitive"
I can't find why.

Abinit takes into account the magnetic symmetries. So maybe you AFM breaks some symmetries what results in a lower space group.
Try without magnetism, you should recover the correct space group.
Usually when constructing a AFM cell, you have to multiply the cell by at least 2 so yes your cell without magnetism may not be primiive.
You can set chkprim to 0 to ignore this fact and continue the calculation with a non primitive cell.