FSM in AKAI KKR

Posted on : September 10, 2024 (Tue) 18:49:19

by Jerzy Goraus

Dear Users and Developers,
is it possible to use fixed spin moment approach in AKAI-KKR, are there any tricks to constrain the moment in the unit cell or on particular atoms?
Sincerely,
Jerzy Goraus

[Re:02] FSM in AKAI KKR

Posted on : October 09, 2025 (Thu) 23:14:35

by Jerry Lee

In AkaiKKR (machikaneyama), if you run a go calculation with magtype set to mag, the stable ferromagnetic state will be calculated automatically (if a ferromagnetic solution exists). For example, if you run a calculation for iron with a body-centered cubic (bcc) structure, the spin moment M = 2.17 μ B is automatically obtained.

In contrast, a calculation method that specifies the spin moment is called a fixed spn moment (fsm) calculation. Looking at the AkaiKKR source code and Installing and Running AKAIKKR (PDF) , it seemed possible to perform fsm calculations. If the calculational mode is set to fsm (ids = 5) then the value for the fixed spin has to be given at the end of the input file.

For example:
c----------------------Fe------------------------------------
fsm data/fefsm
c------------------------------------------------------------
c brvtyp a c/a b/a alpha beta gamma
bcc 5.27 , , , , , ,
c------------------------------------------------------------
c edelt ewidth reltyp sdftyp magtyp record
0.001 1.0 sra mjw mag 2nd
c------------------------------------------------------------
c outtyp bzqlty maxitr pmix
update 8 200 0.035
c------------------------------------------------------------
c ntyp
1
c------------------------------------------------------------
c type ncmp rmt field mxl anclr conc
Fe 1 1 0.0 2
26 100
c------------------------------------------------------------
c natm
1
c------------------------------------------------------------
c atmicx(in the unit of a) atmtyp
0 0 0 Fe
c------------------------------------------------------------
c moment
2.2
c------------------------------------------------------------

[Re:01] FSM in AKAI KKR

Posted on : June 06, 2025 (Fri) 13:36:53

by Jerry Lee

Unfortunately, AkaiKKR is not well-documented; you have to spend a lot of time reading the code yourself.