How to find the direction of spin moments in case of a spiral calculation

Question on input files/tags, interpreting output, etc.

Please check whether the answer to your question is given in the VASP online manual or has been discussed in this forum previously!

Moderators: Global Moderator, Moderator

Post Reply
Message
Author
xianghjun

How to find the direction of spin moments in case of a spiral calculation

#1 Post by xianghjun » Wed May 30, 2007 1:52 pm

Considering a simple system with two Fe ions:

My POSCAR file:
Fe
1.00000000000000
8.0000000000000000 0.00000000000000 0.0000000000000000
0.0000000000000000 8.00000000000000 0.0000000000000000
0.0000000000000000 0.00000000000000 4.0000000000000000
2
Direct
0.5000000000000000 0.5000000000000000 0.0000000000000000
0.5000000000000000 0.5000000000000000 0.5000000000000000

My INCAR file:
IALGO=38
EDIFF=1E-05

EDIFFG = -0.05

ISMEAR=-5
ISPIN=2
SIGMA=0.1
NSW=0
IBRION=2

LPLANE = .TRUE.
NPAR = 1
LSCALU = .FALSE.
NSIM = 4
LREAL=AUTO
ISIF=2
ENCUT=400
PREC=accurate
MAGMOM= 2 0 0 1.17557050458 1.61803398875 0

LORBIT=11
#LWAVE=F

LSPIRAL=.TRUE.

#LASPH=.TRUE.

QSPIRAL = 0.0 0.0 0.3

LZEROZ=.TRUE.

LNONCOLLINEAR =.TRUE.

ISYM=0


Setting LORBIT=11,
I found the following in the OUTCAR file:

magnetization (x)

# of ion s p d tot
----------------------------------------
1 0.060 0.027 2.497 2.584
2 0.060 0.027 2.496 2.584
------------------------------------------------
tot 0.120 0.054 4.994 5.168



magnetization (y)

# of ion s p d tot
----------------------------------------
1 0.000 0.000 0.000 0.000
2 0.000 0.000 0.000 0.000
------------------------------------------------
tot 0.000 0.000 0.000 0.000



magnetization (z)

# of ion s p d tot
----------------------------------------
1 0.000 0.000 0.000 0.000
2 0.000 0.000 0.000 0.000
------------------------------------------------
tot 0.000 0.000 0.000 0.000

But the results seem inconsistent with those specified by "MAGMOM":
MAGMOM= 2 0 0 1.17557050458 1.61803398875 0

I guess the magnetization (M_x, M_y, M_z) given in the OUTCAR file refers to that in the local spin coordinate system, instead of global coordinate system: the magnetization in the global coordinate system should be
M_x(global) = M_x cos(2pi*q.R) + M_y sin(2pi*q.R)
M_y(global) = M_y cos(2pi*q.R) + M_x sin(2pi*q.R)
M_z(global) = M_z
In the current case, q=(0,0,0.3), R(second iron)=(0.5, 0.5, 0.5)
In this way, it will agree with the input magnetizations.
Is this right?

Thank you in advance.
<span class='smallblacktext'>[ Edited ]</span>
Last edited by xianghjun on Wed May 30, 2007 1:52 pm, edited 1 time in total.

xianghjun

How to find the direction of spin moments in case of a spiral calculation

#2 Post by xianghjun » Fri Jun 01, 2007 4:21 pm

From the OUTCAR, I found
number of electron 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
number of electron 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
augmentation part 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
number of electron 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
augmentation part 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
number of electron 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
augmentation part 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
number of electron 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
augmentation part 16.0000000 magnetization 4.0000000 0.0000000 0.0000000
number of electron 15.9999984 magnetization 3.8730565 0.0000365 0.0000000
augmentation part 7.9604835 magnetization 2.5410569 -0.0001275 -0.0218157
...
number of electron 15.9999984 magnetization 5.3856716 -0.0002200 0.0000000
augmentation part 8.4400544 magnetization 3.7888938 -0.0001542 -0.0040599

This might indicate that the definition of the direction of magnetic moment by MAGMOM is different from that used in OUTCAR.
Could anyone tell me what is exactly happening?
Last edited by xianghjun on Fri Jun 01, 2007 4:21 pm, edited 1 time in total.

Post Reply