Author Topic: Seqential tunneling or coherent tunneling?  (Read 3361 times)

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Offline zhangguangping

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Seqential tunneling or coherent tunneling?
« on: November 8, 2013, 21:08 »
Dear all,

I have a questions on the results of my calculation. The molecule is 44.85369 Angstrom long and is terminated by sulfur atom of thiol at the two ends coupled to Au(111) electrodes. The attachment is the transmission and PDOS. From the length of the molecule, 44 Angstrom is so long, that the electron tunneling should be seqential, or maybe Coulomb blockade may ocurr. But from the PDOS, we can see, the broaden of the molecular level is significant, not like the case in Coulomb blockade, where the molecular energy levels are discrete.

In a finite bisa voltage, the transmission peak dominates the electron transport. The peak is also very small due to the localization of the corresponding molecular wavefunction.

So, is there anyone can tell me, what the transport mechanism for this situation? In my opinion, this is coherent transport, becasue the coupling of the molecule with electrodes are not so weak. This also can be seen from the large magnitude of the transmission peak around 1.5eV above the fermi energy.

Am I right?

I am very sorry for the attachment. I can not post the topic with attachment. I think there is something wrong with the storage of this forum. Please see the attachment here: http://www29.speedyshare.com/ud6gp/download/T-PDOS.png.
« Last Edit: November 8, 2013, 21:10 by zhangguangping »

Offline Anders Blom

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Re: Seqential tunneling or coherent tunneling?
« Reply #1 on: November 11, 2013, 11:01 »
You can use the software to estimate the rates for sequential tunneling, but the formalism used to compute the transmission spectrum is only based on coherent tunneling.

Offline zhangguangping

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Re: Seqential tunneling or coherent tunneling?
« Reply #2 on: November 11, 2013, 12:16 »
You can use the software to estimate the rates for sequential tunneling, but the formalism used to compute the transmission spectrum is only based on coherent tunneling.

Thanks very much for your reply.