[CP2K:9574] convergence problems when melting SiC at high pressure

[hut... at chem.uzh.ch]

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
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-----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]