[Wien] Non convergence of LiNiO2

[shamik chakrabarti]

I have used rev-vdW-DF2 as nlvdw Exc

On Tue, 7 May 2024 at 17:57, shamik chakrabarti <shamik15041981 at gmail.com>
wrote:

> Dear Wien2k users,
>
>                      I am trying to simulate LiNiO2. I have achieved
> volume optimization & c/a optimization so far, however not able to achieve
> the coordinate convergence by using,
> runsp_lapw -orb -fc 1.0 -ec 0.0001 -cc 0.0001 -min. I can list the
> possible causes of non convergence as below;
> (1) Structure is wrong: I think the structure is correct as both the unit
> cell structure used earlier and
> experimental XRD matches well as can be seen by using Vesta.
> (2) Wrong Exc or GGA+U: I have used GGA+U with U=2.45 eV for Ni+3 using
> the reported value of U in earlier calculations. As it is a layered
> structure, I have also tried,
> runsp_lapw -orb -nlvdw -fc 1.0 -ec 0.0001 -cc 0.0001 -min, however both
> GGA+U & nlvdw+GGA+U failed to converge.
> (3) No. of K-points: I have used 280 k-points per unit cell contains 4
> atoms/unit cell.
>
> The calculations are still running & reached upto 100 iterations without
> any sign of convergence. I have tried to converge before adding -min to the
> script by using runsp_lapw -orb -ec 0.0001 -cc 0.0001 for 400 iterations.
> However the simulation do not converge. I am sending the struct file for
> your concern.
>
> Looking forward to listen from you.
>
> with regards,
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
>


-- 
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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