RbBiF4 simulation

Posted on : November 06, 2025 (Thu) 00:58:23

by John Cardiff

Dear All,

I'm trying to simulate disordered RbBiF4, in which cationic sites are occupied by Rb or Bi atoms with the same probability. F atoms occupy interstitial Wyckoff positions 8c with 0.75 probability and 48i with 0.04 probability.
Unfortunately, I wasn't able to make the code converge, despite numerous attempts to tune ewidth, bzqlty and pmix parameters.
Do you have any hint?

The input file for the self-consistent simulation is as follow:


c--------------------RbBiF4------------------------------------
go data/RbBiF4_4
c------------------------------------------------------------
c brvtyp a c/a b/a alpha beta gamma
fcc 11.441912916 1.000000000 1.00000000 90 90 90
c------------------------------------------------------------
c edelt ewidth reltyp sdftyp magtyp record
0.001 1.0 scals pbe nmag init
c------------------------------------------------------------
c outtyp bzqlty maxitr pmix
update 6 1000 0.003tch
c------------------------------------------------------------
c ntyp
3
c------------------------------------------------------------
c type ncmp rmt field mxl anclr conc
RbBi 2 0 0.0 2
37 50
83 50
F8c 2 0 0.0 2
9 75
0 25
F48i 2 0 0.0 2
9 4
0 96

c------------------------------------------------------------
c natm
15
c------------------------------------------------------------
c atmicx atmtyp

0.00000000a 0.00000000b 0.00000000c RbBi

0.25000000a 0.25000000b 0.25000000c F8c
0.75000000a 0.75000000b 0.75000000c F8c

0.77000000a 0.50000000b 0.50000000c F48i
0.50000000a 0.77000000b 0.23000000c F48i
0.50000000a 0.23000000b 0.77000000c F48i
0.23000000a 0.50000000b 0.50000000c F48i

0.50000000a 0.77000000b 0.50000000c F48i
0.77000000a 0.50000000b 0.23000000c F48i
0.23000000a 0.50000000b 0.77000000c F48i
0.50000000a 0.23000000b 0.50000000c F48i

0.50000000a 0.50000000b 0.77000000c F48i
0.77000000a 0.23000000b 0.50000000c F48i
0.23000000a 0.77000000b 0.50000000c F48i
0.50000000a 0.50000000b 0.23000000c F48i

c------------------------------------------------------------
#end
# number of k-point along symmetry line
300
# For fcc bravais lattice, the dispersion relation along
# W-L-G-X-W-K symmetry points (below) is usually calculated.
1/2 1/4 3/4
1/2 1/2 1/2
0 0 0
1/2 0 1/2
1/2 1/4 3/4
3/8 3/8 3/4

Thank you vey much for any help you can give me.