[CP2K:9576] convergence problems when melting SiC at high pressure

[Fernan Saiz]

Hi,
The band gap of beta-SiC is 2.36 eV. What are parameters could be adjusted?

Thanks,

- Fernan

On Tue, Oct 24, 2017 at 8:46 AM, <hut... at chem.uzh.ch> wrote:

> Hi
>
> what do you expect for the band gap of this system?
> For small band gap systems you might need to adjust
> your simulation methods.
>
> regards
>
> Juerg Hutter
> --------------------------------------------------------------
> Juerg Hutter                         Phone : ++41 44 635 4491
> Institut für Chemie C                FAX   : ++41 44 635 6838
> Universität Zürich                   E-mail: hut... at chem.uzh.ch
> Winterthurerstrasse 190
> CH-8057 Zürich, Switzerland
> ---------------------------------------------------------------
>
> -----cp... at googlegroups.com wrote: -----
> To: cp2k <cp... at googlegroups.com>
> From: Fernan Saiz
> Sent by: cp... at googlegroups.com
> Date: 10/22/2017 08:34PM
> Subject: [CP2K:9574] convergence problems when melting SiC at high pressure
>
> Hello,
> I am studying the melting of a 256-atom SiC system at high pressures using
> the Z-method. I face the problem that when the pressure is around 10 o 20
> GPa (obtained by reducing 1% the simulation cell size), the ab-initio
> molecular dynamics at NVE does not converge after several hundred steps. I
> tried reducing the timestep to 0.05 fs with a cutoff of 800 Ry for an
> initial temperature of 9000 K, which after a few hundred steps goes down to
> to some 4000 K and the system starts to melt. However, this system does not
> converge even though I used the CG minimizer with a eps_max 1.0E-6 for the
> inner and outer loops, the preconditioner FULL_ALL with the PADE
> functional. Input script file is attached.
>
> I was wondering if I could receive any useful piece of advice.
>
> Best regards,
>  - Fernan Saiz
> Department of chemistry
> Imperial College London
>
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> [attachment "sic.inp" removed by Jürg Hutter/at/UZH]
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