QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Shan on March 8, 2016, 16:28

Title: "Area of cross section" of Atomic chain
Post by: Shan on March 8, 2016, 16:28

Dear sir,

I want to calculate the resistivity (rho = R*A/l)) of an atomic chain, for that I need to calculate area of cross section first. I am really confused, on how to calculate the area of cross section for the atomic chain. (structure is shown in the figure)

plz help sir. Thank you very much for your time.

Title: Re: "Area of cross section" of Atomic chain
Post by: zh on March 9, 2016, 05:31

You couldn't define the cross area of an atomic chain. The conductivity of such atomic chain may have quantum conductivity, which is given in unit of G0. 

Title: Re: "Area of cross section" of Atomic chain
Post by: Shan on March 9, 2016, 09:31

Then, How can I calculate the quantum conductivity for the atomic chain sir.

Plz help me. Thank you very much for ur time sir.

Title: Re: "Area of cross section" of Atomic chain
Post by: Anders Blom on March 9, 2016, 22:49

Quantum conductance, not conductivity. The conductance is what ATK gives you, from a transport calculation. To compute conductivity (which can be defined also for a chain, but it will not include the area A, it's just "R/L") you also need to include all kinds of scattering mechanisms (i.e. phonons etc).

Title: Re: "Area of cross section" of Atomic chain
Post by: Shan on March 10, 2016, 08:17

Dear sir,

1) If conductivity does not include area, the new units of conductivity will be s-m instead of s/m.  Will it be valid???

2) I have computed I-V curve for the LAC, does it include the scattering mechanisms (i.e phonons etc) by default ??. If not, how to include them in the I-V calculation.

Thank you very much for ur time sir.

Title: Re: "Area of cross section" of Atomic chain
Post by: Anders Blom on March 11, 2016, 13:08

Quote from: Shan on March 10, 2016, 08:17

1) If conductivity does not include area, the new units of conductivity will be s-m instead of s/m.  Will it be valid???

Yes, the unit changes with dimensionality.

Quote from: Shan on March 10, 2016, 08:17

2) I have computed I-V curve for the LAC, does it include the scattering mechanisms (i.e phonons etc) by default ??. If not, how to include them in the I-V calculation.

Not by phonons. For that, see http://quantumwise.com/publications/tutorials/item/877-inelastic-electron-spectroscopy-of-h-molecule-between-1d-au-chains and http://quantumwise.com/publications/tutorials/item/837-inelastic-transmission