The ABINIT Users Mailing List ( CLOSED )

[Xinjie Wang <xinjie@physics.rutgers.edu>]

Dear Nicola,

Thanks for the nice comments.

Regards,
Xinjie

Nicola Marzari wrote:
> One side comment - it can become more efficient if the unit cell 
> contains many inequivalent atoms.
>
> Suppose you have 100 atoms - usually, you would need to displace each of 
> them, one by one, in the three crystallographic directions, and
> calculate the resulting polarization (this can be done either with
> linear-response theory, i.e. as the response to an infinitesimal 
> displacement, or with the Berry phase, as the response to a finite one).
>
> Instead, you can apply a small electric field three times (in 3 non 
> equivalent directions), and you have right away the effective charges 
> for all the 100 atoms. Similar considerations apply, say, if you wanted
> to calculate Raman couplings.
>
>
>                 nicola
>
>
> Xinjie Wang wrote:
> > Hi David,
> >
> > This feature (B.10) does not give more efficient/accurate calculations
> > of the static dielectric properties. It allows the calculation of
> > electric-field-dependence of Born effective charges and dielectric 
> > tensor. You can read this paper, Phys. Rev. B 75, 115116 (2007),
> > for details.
> >
> > Regards,
> > Xinjie
> >
> > david.hendry@mandmd.com.au wrote:
> > > Dear Abinitors,
> > >
> > > I'm interested in the static dielectric constant of 
> > > ceramics/insulators.  I notice the latest release notes of Abinit: 
> > > "B.10 Born effective charges and dielectric tensor calculations can 
> > > now be computed in a finite electric field." Does this feature or any 
> > > other new feature (from 5.3.4) allow a more efficient/accurate 
> > > calculation of the static dielectric properties?
> > >
> > > Sincerely,
> > >
> > > David.