[DFTB-Plus-User] ohmic resistance

Sascha Thinius sascha.thinius at thch.uni-bonn.de
Tue Dec 9 14:52:24 CET 2014


Thanks Gabriele,

> as you can apply a bias and calculate the current, you can calculate
> trivially the conductance.
That is clear as daylight.

> The conductivity (or resistivity) on the other hand can be calculated
> indirectly, as you can extract the mean free path from the transmission
> probability, similar to linear response theory.
Not clear at all how this should work. How I can extract the mean free 
path from a transmission probability of the form T(E)? But note, I am 
a completely newbie in this field.


> You may want to give a look to S. Datta or M. Lundstrom books, among the others.
> There is also quite a lot of literature where Landauer is used to calculate mean 
> free paths.
I found a formula of the form

G-1 = L / sigma W + L0/sigma W

Where 'W' represents the width of the conductor.
Doing at minium two calculation with different length I should be able 
to calculate the conductivity 'sigma' from the slope and the mean free 
path from the axis intercept.
Is that OK, or bad practice?


Cheers,

Sascha.

On Mon, 08 Dec 2014 16:24:03 +0100
  Gabriele Penazzi <gabriele.penazzi at bccms.uni-bremen.de> wrote:
> On 12/08/2014 03:34 PM, Sascha Thinius wrote:
>> Dear all,
>>
>> Is it possible to extract an ohmic resistance or conductivity from a
>> dftb+negf calculation?
>> Does somebody know how?
> 
> Dear Sascha,
> 
> as you can apply a bias and calculate the current, you can calculate
> trivially the conductance.
> 
> The conductivity (or resistivity) on the other hand can be 
>calculated
> indirectly, as you can extract the mean free path from the 
>transmission
> probability, similar to linear response theory. You may want to give 
>a
> look to S. Datta or M. Lundstrom books, among the others. There is 
>also
> quite a lot of literature where Landauer is used to calculate mean 
>free
> paths.
> 
> Gabriele
> 
> 
>>
>> Thanks,
>>
>> Sascha.
>> _______________________________________________
>> DFTB-Plus-User mailing list
>> DFTB-Plus-User at mailman.zfn.uni-bremen.de
>> https://mailman.zfn.uni-bremen.de/cgi-bin/mailman/listinfo/dftb-plus-user
> 
> _______________________________________________
> DFTB-Plus-User mailing list
> DFTB-Plus-User at mailman.zfn.uni-bremen.de
> https://mailman.zfn.uni-bremen.de/cgi-bin/mailman/listinfo/dftb-plus-user



More information about the DFTB-Plus-User mailing list