# transmission spectrum

Hi,
Can you explain the physical meaning of transmission spectrum plotting using .AVTRANS_Left-Right file?

## Question information

Language:
English Edit question
Status:
Solved
For:
Siesta Edit question
Assignee:
No assignee Edit question
Solved by:
Nick Papior
Solved:
2019-07-30
Last query:
2019-07-30
2019-07-30
 maluneelambari (maluneelambari) said on 2019-07-30: #1

Adding fewmore doubts. .AVTRANS_Left-Right gives total transmission.
1.How does it related to transmission co-efficient which uses in the Landauer-Büttiker formula for current?
2.Total transmission can be more than one and transmission co efficient comes between 0 and 1, isn't?
3.What all output values in the tbtrans calculation are used to calculate current?

Thanks.

 Nick Papior (nickpapior) said on 2019-07-30: #2

1) It is the Landauer-Buttiker formula
2) Yes, the transmission eigenchannels are between 0 and 1
3) The total transmission and the chemical potentials.

 maluneelambari (maluneelambari) said on 2019-07-30: #3

Thanks for the reply. But if you give some more clarifications it would help me for better understanding.

1. Is the values in the .AVTRANS file is used as T(E) in the Landauer-Buttiker formula ?
2. a)Transmission spectrum plots using .AVTRANS file is between energy of electrons and total transmission through the device. Isn't it?
b) This can be more than 1. Right?
3. How does transmission eigenchannels(.TEIG) values and .AVTRANS values are related ?

 Nick Papior (nickpapior) said on 2019-07-30: #4

1) yes
2a) AVTRANS contains the total transmission T(E) from a given electrode to another electrode
2b) Yes
3) The sum of TEIG equals the AVTRANS transmission. If they don't, then you need to calculate more eigenchannels.

For further details, you can either: