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Topics - kstokbro

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Scripts, Tutorials and Applications / Capped carbon nanotubes
« on: February 19, 2014, 11:39 »
Here are some capped carbon nanotubes:

The attached script can calculate the k-dependent DOS of a bulk system.

Below is a script which calculates the minimum decay of the complex bands in the brillouin zone. If there are real bands, the decay is zero,
have fun

Gallery / Non collinear spin
« on: March 13, 2013, 09:54 »
The figure shows the local spin direction in a 2-probe non-collinear calculation.
The system is a 2D Iron layer, periodic in y direction, and modelling transport along z.
Left electrode: spin direction y,  Right electrode: spin direction –y

This feature and many others will be available in  ATK13.8, we project to sent out a beta release in august 2013

Gallery / Local density of states for a metal-organic interface
« on: February 1, 2013, 13:23 »
I am currently studying a metal-organic interface between Au(111) and a pentacene crystal. The plots below show the electronic structure at the interface. The LDOS  shows the DOS as function of z in the energy range [-2,2] eV. You can clearly see the 5 gold layers, and the 4 molecular states of the pentacene layers. Note the band bending in the pentacene crystal.

Gallery / Your Valentines molecule
« on: July 9, 2012, 07:53 »
I wanted to see if I could build a heart molecule with the new builder. It was not so difficult,
build a capped nanotube, cut it, mirror it, and put the two together.

The molecule is stable, and you can perform MD simulations with the molecule above 1200 K, without collapsing the molecule

Plugin Development / Quantum espresso import/export plugin
« on: June 11, 2012, 23:20 »
There is now a new plugin which can import and export the geometry from  PWSCF.

The plugin is installed by opening the addon manager (via help menu in VNL) and install the plugin called espresso filters.
You can now import/export pwscf geometries in the new builder.
Please post if you find any problems/structures that are not imported/exported correctly

Gallery / new painting at QuantumWise
« on: November 16, 2011, 11:24 »
If you visit Copenhagen, we would like to invite you to our office at Lersø Parkalle 107, to obtain feedback on our products and suggestion for new features.
You may see our new 2m x 1.5m painting, by artist Laura Stokbro.

Gallery / Energy dependent LDOS for a benzene device
« on: August 8, 2011, 21:16 »
The attached figure shows the LDOS along z (averaged over x and y), for DTB coupled with gold electrodes. Note how the high density of states coincides with the resonances in the transmission spectrum. I also attach the scripts used for generating the figure.

We have discovered that The custom nanowire builder in atk11.3 and earlier versions calculates an incorrect lattice constant in the wire direction.

The attached custom builder script will setup the nanowire correctly. Each time you want to use it you must drop the script on the custom builder.
In the next version of ATK this problem will be corrected.

Please find a script for calculating moments of the transmission spectrum, from which the following transport coefficients can be obtained:
Seebeck coeffient, thermal conductance, conductance, Peltier coefficient and ZT

It is based on PRB 73, 085406 (2006)

Output for Li-H2-Li system:
Conductance               =  5.42244762598e-05 S         =  0.699842983718 G0
Peltier Coefficient       =  -1.52243834955e-05 eV/e
Seebeck Coefficient    =  -5.07479449851e-08 V/K    =  -0.000588904769171 kb/e
Thermal Conductance =  3.89878290707e-10 J/s/K
ZT                                =  1.0745447041e-07

I attach a custom analyzer for calculating the band gap of a band structure

Drop the script on the custom analyzer tool

You can generate some data with the file

drop the file in the drop zone and get the attached plot,

Have fun,

NOTE: The version of the script attached to this post works for ATK 10.8. For ATK 11.2, see post below.

Can anybody help me with a script that converts a two-probe system into equivalent bulk?

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