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QuantumATK => General Questions and Answers => Topic started by: sweta on May 20, 2016, 12:27

Title: asymmetric molecular junctions
Post by: sweta on May 20, 2016, 12:27

Hello all,

I am working on asymmetric molecular junctions. I want to take left side electrode of some metal Au (say), a molecule in the middle connecting to the electrodes through some anchoring group. I want to know what are the possibilities of taking right side electrode.
Can we build junction by taking right electrode like graphene, nanotube, Au/Ag interface etc.  Please suggest me the possibilities of asymmetric junction that use two different type of electrodes which can be build in ATK-VNL.

Thanks in advance!

Title: Re: asymmetric molecular junctions
Post by: Daniele Stradi on May 20, 2016, 12:55

Dear Sweta,

there is absolutely no problem in doing heterogeneous systems such as asymmetric junctions, where "heterogeneous" means that the right and left electrodes are not the same.

Here you can find two articles with calculation on heterogeneous systems:
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.88.075317
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.93.155302

Title: Re: asymmetric molecular junctions
Post by: sweta on May 23, 2016, 11:09

Thank you for your reply.

I want to build hetero-junctions in ATK, some images of which are attached herewith. Can anyone help how to build these junctions in ATK???

Title: Re: asymmetric molecular junctions
Post by: Anders Blom on May 23, 2016, 14:07

These are pretty easy to build, really, if you first follow some of the tutorials for the Builder. You make the corresponding left and right parts, the molecule, combine them, align them, all simple operations in the Builder using the Move tool etc.

Title: Re: asymmetric molecular junctions
Post by: sweta on May 30, 2016, 14:02

Thanks Blom for reply.

 I build structure similar to M5 of the previous attached file. I took left electrode of armchair graphene of width 7 and right electrode of Au (3x3). When it drag into interface and create then right Au becomes (6x6) i.e. six atoms in vertical direction. why it happens???

Title: Re: asymmetric molecular junctions
Post by: Jess Wellendorff on June 1, 2016, 08:58

Sounds like your Au electrode needs to be repeated in order to fit with the graphene. Perhaps you need to manually repeat the electrode along one or two directions only in order to avoid this.

Title: Re: asymmetric molecular junctions
Post by: Aadhityan on June 4, 2016, 11:05

Follow below tutorial to build one side Au electrode. Then draw graphene and the molecule in separate builder.  After that just copy the graphne and molecule then paste it to your Au electrode.

https://www.youtube.com/watch?v=aoErF-WpU0c