[Wannier] Energy mismatch among symmetry equivalent states in silicon

[Mostofi, Arash]

Dear Vahid
Does the same discrepancy arise if you wannierise just the four valence bands, or does it only occur when you disentangle 8 WFs? If the latter, you may need to adjust you disentanglement settings to get a better set of WFs.
Best wishes
Arash 
--
Departments of Physics & Materials
Imperial College London

Sent from my iPhone

> On 31 Aug 2016, at 23:05, Vahid Askarpour <vh261281 at dal.ca> wrote:
> 
> Dear Wannier Users,
> 
> I have calculated the interpolated band structure of silicon (8 wannier functions) using a k grid of 8x8x8. I considered two segments:
> 
> 1. From 0.05 0.4 -0.4 to 0.05 0.4 -0.5
> 2. From 0.85 0.4 0.3 to 0.85 0.4 0.4
> 
> My purpose in choosing these two segments is to compare the electronic energies at two symmetry equivalent points: (0.05,0.4,-0.45) and (0.85,0.4,0.35).
> 
> Here are the eight band energies (in eV) for the two points:
> 
> -2.2651301     -2.262256
> -0.7977982    -0.7918293
> 2.5481431      2.5474092
> 3.3210793      3.4353798
> 7.3564264      7.340448
> 8.7099476      8.6832805
> 14.055428      14.064489
> 14.828398      14.849574
> 
> In case of diamond, these energies are identical. But for silicon, for example, band 4 is different by 100meV! Has anyone encountered this energy mismatch
> and is there a way to deal with it?
> 
> Thank you,
> 
> Vahid
> 
> 
> Vahid Askarpour
> Department of Physics and Atmospheric Science
> Dalhousie University,
> Halifax, NS, Canada
> 
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