About obtaining the single ion anisotropy

[Jaime Garrido]

Hi, TB2J users

I know TB2J does not calculate single ion anisotropy yet, but I was wondering if it is even possible to calculate it using the theoretical formalism behind TB2J. If so, are there plans to implement it in the future?

If it is not possible to calculate with the formalism, do you know any way to calculate it?

The only way I can think about is using constrained DFT for several magnetic configurations and mapping the differences in energies to the Heisenberg hamiltonian including the single ion anisotropies. Knowing the exchange constants given by TB2J would help in this mapping.

What do you think about it?

Jaime

[Xu He]

Hi Jaime, 

It is on the to-do list.  Certainly, this is a very important feature. And not having it is one of the reasons why the version number of TB2J does not reach 1.0 yet. 

Best regards, 

HeXu

[matthieu verstraete]

Hello Jaime,

The common method to get SIA and MAE is as you say a fit to constrained DFT, has been used for years and works fine. 

There is a plan to include this in tb2j but it's not completely trivial and not done yet. You need more information than a single snapshot set of wannier functions and a single hamiltonian matrix, but not much more. Ideally you want the spin state to change (spin from z to x) but the WF to stay the same, which is not trivial.

Best

Matthieu

--
You received this message because you are subscribed to the Google Groups "TB2J" group.
To unsubscribe from this group and stop receiving emails from it, send an email to tb2j+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/tb2j/9c35e588-8660-482f-99ba-473f64d16a27n%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Professor Matthieu J Verstraete

Fellow, American Physical Society

Chair, Steering Committee, European Theoretical Spectroscopy Facility www.etsf.eu

Alumnus Fellow, Young Academy of Europe  yacadeuro.org

Institute for Theoretical Physics (ITP) Department of Physics

Buys Ballot Gebouw/Building, Princetonplein 5, office 

University of Utrecht,  3584 CC Utrecht

ITP Secretariat: +31 30 253 5928 E-mail: science....@uu.nl

Group web page (Liège): http://www.nanomat.ulg.ac.be/

Nanomat lab, Q-Mat center, Université de Liège
Département de Physique, Bat. B5a, 4/50
Allée du 6 août, 19 B-4000 Sart Tilman, Liège Belgium
Phone : +32 4 366 90 17

European Theoretical Spectroscopy Facility (ETSF)

Mail : matthieu....@uliege.be
          matthieu.jea...@gmail.com

          m.j.ver...@uu.nl