Hi Shi,
In many systems, as in the case of the oxygen molecule, $O_2$, the system is
more stable when adding spin polarization (look in Wikipedia, for example, for
a simple description). The same could happen to your system.
On the other hand, the value you obtain depends on the actual electronic
structure of the ground state. In the previous case of the oxygen molecule it
was 2. Here it happens to be 4.
Finally, the value is given in bohr magnetons.
Hope I have successfully answered all your questions.
Sincerely,
Adolfo
On Apr 6, 2012, at 3:19 AM, shihitwh wrote:
Hi,all
I use the siesta to calculate the spin polarizaiton of a Ti doped system
without magnetic materials. When no spin-polarized, the total energy is
-9276.290371 eV; while adding the spin polarizaiton, the total energy is
-9279.474363 eV, and it shows "Total spin polarization (Qup-Qdown) =
4.000000" in the output file. My question are :1. Do the calcaluted total
energy trend is right, adding the spin polarization causing the absolute value
bigger? 2. Is it possible that Qup-Qdown value is "4"? 3. Which unit is the
"Total spin polarization"?
Best Wishes!
Shi
&nb sp; 2012.4.6
