[Pw_forum] high-frequency dielectric constant of SrTiO3

[Stefano Baroni]

Have you tried linear response? have you performed any convergence  
test 9especially wrt the number of k points)? SB

On Jul 9, 2008, at 10:48 AM, alan chen wrote:

> Dear PWSCF users,
>       I am calculating the high-frequency dielectric constant of  
> SrTiO3. Using the method given in the example31, I calculate  
> D[E=0.001a.u.] and D[E=0] and eps_inf=4*pi*(D[E=0.001a.u.]-D[E=0])/ 
> (0.001a.u.*Omega) + 1 where Omega is the volume of the unit cell.
>       I sample the Brillouin zone by 4x4x8 (uniformly distributed)  
> and obtain: D[E=0.001 a.u.] = 0.155 and D[E=0] is almost zero,  
> therefore eps_inf=6.0 which is much smaller than experimental values.
>       Did I do the calculation correctly? Does anyone have  
> experience about calculating high-frequency dielectric constant of  
> SrTiO3?
>       Thank you very much.
>
> Hanghui
> Department of Physics,
> Yale University
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
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