what's DFT+Σ method?

[wot19920302]

Dear Quantumwise staffs:
       I have a question about DFT+Σ. We know in ATK we can use DFT+U to get better energy band. But recently I received a paper review. The reader recommended we use  DFT+Σ to calculate LUMO-HOMO gap. So what's DFT+Σ method?  Can we use it in ATK?
       Best

[Petr Khomyakov]

I can only guess that DFT+Σ might refer to a many-body method such as GW. This kind of many-body approaches are not implemented in the ATK yet. I note that the GW is computationally extensive, not really practical for large systems. We are currently working on implementing the hybrid functional approach such as HSE, which is less expensive, but often provides the GW accuracy for energy gap calculations.

[Daniele Stradi]

Hi,

no the DFT+Sigma method as defined by Neaton and Luoie (see for example http://pubs.acs.org/doi/abs/10.1021/nl3033137) is not implemented.
In the newest ATK version is possible to use alternative methods such as the PseudoPotenitalProjectorShift as an alternative method to DFT+Sigma:
http://docs.quantumwise.com/manuals/Types/PseudoPotentialProjectorShift/PseudoPotentialProjectorShift.html

Regards,
Daniele.