The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

On 09 Jul 2007, at 23:04, hbao@purdue.edu wrote:

> Dear all,
> I am using abinit to calculate band structure of anatase TiO2. The  
> band gap is good and trends is good too. However, the bands are not  
> smooth curves. Instead, they are fluctuating, especially at higher  
> energy levels. What might be the reason for that?

Dear hbao,

One reason might be that your basis set (number of plane waves) is  
fluctuating abruptly with the different k points,
hence the discontinuities. The standard way to correct this problem  
is to smooth the incorporation of plane waves,
with a non-zero value of the input variable ecutsm, typically 0.5 Ha.

Good luck,
Xavier