[Pw_forum] magnetic moment

[Guido Fratesi]

On 10/11/2012 04:10 PM, Sakhrawi Taoufek wrote:
> i read that the value of starting magnetization is used to brake the
> up/dw symmetry  in the charge density but when i fix all parameters and
> i change the values of starting magnetization the value of total
> magnetization and
> the magnetic moment of each atom changes. U can't understand the
> relation between starting magnetization, total magnetization and the
> local magnetic moment
> there is any adea??
> thinx

Starting magnetization is about the initial guess of the SCF cycle.

Total/local magnetization is about the converged (or willing to 
converge) spin-dependent charge density.

May the difference in the two concepts be not clear to someone, some 
textbook reading could be recommended.

If the system is "easy", the final result should not depend on the 
initial guess. That is not always the case, unfortunately, as magnetic 
structures often display several E[\rho] minima so you might need to 
play a bit with the starting guess to cover all possibilities and find 
the global minimum.

Guido


-- 
Guido Fratesi

Dipartimento di Scienza dei Materiali
Universita` degli Studi di Milano-Bicocca
via Cozzi 53, 20125 Milano, Italy