I'm writting to you concerning some understanding issues on my side while conducting spin-spiral calculations. Especially the spin-spiral groundstate of gamma-Iron, given as an example lead to some confusion
The given elk.in is clear except the applied field through out the unit cell "bfieldc", as the direction under investigation is supposed to be [qq0] with a fixed q of [0.1,0.1,0] for the given example.
! spin-spiral q-vector in lattice coordinates
vqlss
0.1 0.1 0.0
! spiral magnetic field along q with perpendicular component only
bfieldc
0.05 0.00 0.0
Condensing this to one question as: "Why isnt the field applied along q with two finite components (b_x,b_y,0) ?"
I'd be happy to be enlightened by an expert and thanks in advance.
Lukas
Last edit: lwollmann 2015-01-19
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Since spin-orbit coupling cannot be included in a spin spiral calculation,
the real/reciprocal space and spin space are not coupled, i.e. they are independent of each other.
A spin spiral is then taken to always rotate around the z-axis in spin space in ELK. For instance a planar spin spiral is in the xy-plane in spin space, as specified by bfieldc in your case. The exact direction within this plane is irrelevant since it is only specifying the direction of one atomic site within an infinite spin spiral ...
However, the wave-vector can point in any direction in reciprocal space - as specified by vqlss.
In short the answer is that the two vectors are completely independent.
Good luck,
Lars
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Dear developers and users,
I'm writting to you concerning some understanding issues on my side while conducting spin-spiral calculations. Especially the spin-spiral groundstate of gamma-Iron, given as an example lead to some confusion
The given elk.in is clear except the applied field through out the unit cell "bfieldc", as the direction under investigation is supposed to be [qq0] with a fixed q of [0.1,0.1,0] for the given example.
Condensing this to one question as: "Why isnt the field applied along q with two finite components (b_x,b_y,0) ?"
I'd be happy to be enlightened by an expert and thanks in advance.
Lukas
Last edit: lwollmann 2015-01-19
Dear Lukas,
Since spin-orbit coupling cannot be included in a spin spiral calculation,
the real/reciprocal space and spin space are not coupled, i.e. they are independent of each other.
A spin spiral is then taken to always rotate around the z-axis in spin space in ELK. For instance a planar spin spiral is in the xy-plane in spin space, as specified by bfieldc in your case. The exact direction within this plane is irrelevant since it is only specifying the direction of one atomic site within an infinite spin spiral ...
However, the wave-vector can point in any direction in reciprocal space - as specified by vqlss.
In short the answer is that the two vectors are completely independent.
Good luck,
Lars