QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: hol28 on August 6, 2012, 03:00

Title: How to calculate the charge transfer?
Post by: hol28 on August 6, 2012, 03:00

Hi everyone:
In this topic, http://quantumwise.com/forum/index.php?topic=369.0, the author calculated the charge transfer in the system. I'm also studying the effect of the gate voltage on the charge of the central region in a two-probe system. I know that the mulliken population can give the charge of an given atom. Is there another way to calculate the charge transfer?
Any advice would be appreciated!

Title: Re: How to calculate the charge transfer?
Post by: mads.engelund on August 9, 2012, 09:21

Hmm, an alternative to the Mulliken population could be using the ElectronDensity.
A rough example I have made:

Code

ed = nlread('analysis.nc', ElectronDensity)[0]
cut = 20
s = ed[:, :, :].sum()
print ed[:,:, :cut].sum()/s
print ed[:,:, cut:].sum()/s

Where 20 is some grid number in the z-direction.

Also take a look at the manual entry for ElectronDensity :)

Title: Re: How to calculate the charge transfer?
Post by: hol28 on August 28, 2012, 16:51

Thank you very much! I will have a try.

Quote from: mads.engelund on August  9, 2012, 09:21

Hmm, an alternative to the Mulliken population could be using the ElectronDensity.
A rough example I have made:

Code

ed = nlread('analysis.nc', ElectronDensity)[0]
cut = 20
s = ed[:, :, :].sum()
print ed[:,:, :cut].sum()/s
print ed[:,:, cut:].sum()/s

Where 20 is some grid number in the z-direction.

Also take a look at the manual entry for ElectronDensity :)

Title: Re: How to calculate the charge transfer?
Post by: esp on November 4, 2012, 06:02

 I am going to try this as well .. question .. if have a 16nm long 2 probe GNR device, and i want to calculate the charge in the channel, would it be quicker in terms of computation time run the mulliken pop calc or the electron density calc?

Title: Re: How to calculate the charge transfer?
Post by: Nordland on November 4, 2012, 08:59

If you want to calculate the charge in a region, the only measure is the electron density, and it is not much slower than the mulliken population.