David, thank you so much! This definitely did the trick. However, I was wondering if anyone could really shed light on the problem with the PAW PP. Is there really something I (and I understand, by extension, you as well) am missing here? Yours, Daniel
On Sun, Feb 9, 2020 at 4:36 PM David Guzman <[email protected]> wrote: > Hello Daniel, > I am currently currently working on an AFM system as well and was having > exactly the same problems you described. > I am not sure, but changing the pseudopotentials seem to have solved my > problems. Not sure if there is something wrong with those paw > pseudopotential or if there are extra setting that should go along with > those potentials. > Maybe you can try the ONCVPSP pseudopotentials to see if you get better > results. > > Regards, > David G. > Brookhaven National Laboratory > > > On Feb 9, 2020, at 9:10 AM, Daniel Kaplan <[email protected]> > wrote: > > > Hello All! > > I'm trying to calculate a system with a *known* AFM ground state. In the > attached example, I provide the input data I'm using for CuMnAs -- a > tetragonal anti-ferromagnet. > I've started on this project by first executing the examples, and > particularly FeO. > I tested this example against all sorts of variations: different > functionals, with/without U, and so on. Without any further tweaking, the > system always converged to the AFM ground-state, provided the initial > moments were also oriented in the AFM configuration. > > Which makes my failure in this (CuMnAs) system even more puzzling. > Firstly, *without* any constraints, the system does not converge to an > AFM state. > 1. Using 'constrained_magnetization=total' leads to completely wrong > results, with a divergent "Magnetic field". > 2. A more-or-less sensible result can be obtained with > 'constrained_magnetization='atomic' (as shown), however, the resultant > magnetization is not altogether anti-ferromagnetic. Note that the system is > in general endowed with PT-symmetry. The resultant eigenvalues *DO NOT* show > this and you can also see the disparity in the magnetic moments of the Mn > atoms, as well as eigenvalue difference of more than 1meV for some bands > and k-points. > 3. This behavior is *weakly* dependent on lambda. I tried fiddling around > with the values. A certain increase worsens the results, then seems to > improve it, only to worsen again. What is a reason value for the > constraint, in your estimation? I take it to be 5% of the unperturbed > energy (i.e., energy without the constraint). > 4. Testing the *exact* same system on different software (VASP, in this > case), converged very well to the AFM state (i.e., PT symmetry was > recovered to less than 1meV). > > What am I doing wrong, therefore? > I would appreciate any advice. > Yours thankful, > Daniel Kaplan > Dept. of Condensed Matter Physics > Weizmann Institute of Science > <scf.in> > <scf.out> > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users > > _______________________________________________ > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso) > users mailing list [email protected] > https://lists.quantum-espresso.org/mailman/listinfo/users
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