Dear All,
When I am trying to do FSM calculations to fcc-Fe, I met such strange things:
The equilibrium volume of magnetic fcc-Fe is about 72 (au)^3, and nonmagnetic
one about 70 (au)^3(PRB,60, 3839).
When I fixed the magnetic moment, the total energy decreases with the increase
of the volume over all the volume range I used: from 50 (au)^3 to 120(au)^3.
One of the input is as follows: (in other calculations I just vary the
celldm(1) )
&CONTROL
title = fcc-fe ,
calculation = 'scf' ,
restart_mode = 'from_scratch' ,
outdir = './' ,
pseudo_dir = './' ,
wf_collect = .true.,
tstress = .true.,
prefix = pwscf,
tstress = .false. ,
/
&SYSTEM
ibrav = 2,
celldm(1) = 6.60,
nat = 1,
ntyp = 1,
ecutwfc = 30 ,
degauss = 0.01,
ecutrho = 350,
smearing = 'mp',
occupations = 'smearing',
nspin = 2,
constrained_magnetization = 'total',
fixed_magnetization(3) = 0.0
/
&ELECTRONS
/
&IONS
/
&CELL
/
ATOMIC_SPECIES
Fe 55.84700 Fe.pw91-sp-van_ak.UPF
ATOMIC_POSITIONS alat
Fe 0.000000000 0.000000000 0.000000000
K_POINTS automatic
20 20 20 1 1 1
I do not know the reason. And the total energy is twice as the nonmagnetic
calculation (nspin=1) . In my mind they should be the same if I set total
moment to 0.0
Regards and happy weekend!
Dr. Wenxu Zhang
State Key Laboratory of Electronic Thin Films and Integrated Devices,
University of Electronic Science and Technology of China,
Chengdu 610054
China
Tel: +86-28-83201475
Fax: +86-28-83204938
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