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Particle in an octopus

Octopus can actually run 2D systems where the shape of the simulation box is defined by what is white in an image file. Here is an example of a “particle in an octopus”, in which we have a constant potential and an octopus-shaped quantum dot. To run it, you will need to have built the code with the optional library GDLIB.

Input

For this example we will need two files:

inp 


CalculationMode = gs
FromScratch = yes
Dimensions = 2

%Species
"null" | species_user_defined | potential_formula | "0" | valence | 1
%

%Coordinates
"null" | 0 | 0
%

BoxShape = box_image
BoxShapeImage = "gdlib.png"

ff = 20
%Lsize
 135 / ff | 95 / ff
%

TheoryLevel = independent_particles
ConvEigenError = yes

%Output
  wfs | plane_z
%

Gdlib.png

Make this file available in the run directory. You can download it by clicking on the image bellow. It is also available in the PREFIX/share/octopus directory from your Octopus installation.

Plotting

The wavefunction are obtained by using:


 %Output
   wfs
 %
 OutputFormat = plane_z

View it in gnuplot with

 plot 'static/wf-st0001.z=0' u 1:2:3 linetype palette

or

 splot 'static/wf-st0001.z=0' u 1:2:(0):($3*500) with pm3d

Where does the wavefunction localize, and why?

Exercises