[Pw_forum] Improve convergence, slab and electric field.

joaquin peralta jperaltac at gmail.com
Mon Aug 30 21:43:44 CEST 2010

Dear Tone

Thanks you so much for the answer.

> >    edir                  = 3
> >    emaxpos               = 0.9
> >    eopreg                = 0.2
> >    eamp                  = 0.019447
> > /
> This input explains why you face SCF problems: they are inevitable with
> your dipole-layer specification. You have placed your dipole layer
> from 0.9 to 0.9+0.2=1.1. Note that position of emaxpos/eopreg is in
> internal units, in range [0,1].

Now I'm a little bit confused, because i use a previous thread about that


What I have to do?

>From you other email I assume your z-lattice vector is 140 bohr long,
> and your Al slab extends from z=0 to z=82 bohr. Based on this data, a
> good choice of emaxpos & eopreg would be:
> Sorry, I have now a slab put in the middle of the cell in the Z axis,  from
z=32 to z=50 (maximum).

An important thing when applying strong electric fields (which is your
> case) is to check against the electron field emission (i.e. that a
> fraction of electrons doesn't spill to a dipole layer). This can be
> verified by inspecting a charge density in the vacuum region (or even
> better a charge density difference between a slab under electric field
> and no field).

Really thanks, I will check this when I obtain some results, using E-Field.

Joaquin Peralta

Group of NanoMaterials
Joaquín Andrés Peralta Camposano

In a world without frontiers,
who needs Gates and Win.
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