Simulate vacuum in scattering region in TranSiesta

Asked by Nikolay Patyukov on 2018-11-22

I'm trying to use TranSiesta to simulate small model of vacuum nanoeletronic device with electrodes. For now I'm just started and calculating current and transmission of simple Silicon wire that consist of 11 atoms (2|7|2). However, when I'm trying to remove 6-th and 7-th atom, there is zero current calculated with tbtrans at any applied voltage, tried voldate up to 10 eV. Are there some general recommendations to modify .fdf file of scattering region to introduce a vacuum layers inside scattering region?

Sorry if my question is dumb, I've just started working with all of this. Thank you in advance!

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Last query:
2018-12-10
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2018-12-10
Launchpad Janitor (janitor) said : #1

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Nikolay Patyukov (biggysmallz) said : #2

Thank you for the clarification.

8 дек. 2018 г. 12:04 PM пользователь "Launchpad Janitor" <
<email address hidden>> написал:

> Your question #676306 on Siesta changed:
> https://answers.launchpad.net/siesta/+question/676306
>
> Status: Open => Expired
>
> Launchpad Janitor expired the question:
> This question was expired because it remained in the 'Open' state
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Nick Papior (nickpapior) said : #3

You can't have current flowing between two regions if there is no matrix element coupling them.

Nikolay Patyukov (biggysmallz) said : #4

Thank you very much for answer, Nick Papior!

I wonder if there is a way to properly simulate vacuum layer as a matrix element. May be it should be some specific pseudopotentials. I know that "ghost" atoms can be used to simulate a vacancy in crystal, but it seems different from what I want. I'm looking for something that would be physically correct to calculate ballistic-like (tunneling) electron current through vacuum under applied bias, if it is possible within Siesta method.

Thank you in advance!

Nikolay Patyukov (biggysmallz) said : #6

Thank you! I will look at this today, it seems like it.

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