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Quantum Dots and MATLAB

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Dylan Gorman

Dylan Gorman

March 19, 2010 11:19pm UTC

Quantum Dots and MATLAB

Hi folks,

I am trying to model a particular quantum dot in COMSOL. I am placing a number of electrodes on top of a substrate, specifying an electric potential on each of them, and solving Poisson's equation for the electric potential everywhere in the 3d model.

What I want to do is write a MATLAB routine that will vary the potential defined on one of the electrodes, and with each iteration I want to obtain the electric potential V(x,y,z), and feed this into an external density functional theory solver to calculate electron configurations.

The first problem I am running into that I cannot seem to find in the manual is that the solution, fem.sol.u, is a 1d array. I need somehow to obtain the real space representation V(x,y,z) from fem.sol.u.

I would appreciate any input that folks can offer on this (probably naive) question.

Thanks!
Dylan

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Waleed Shinwari

Waleed Shinwari

May 31, 2010 1:39am UTC in response to Dylan Gorman

Re: Quantum Dots and MATLAB

This is not a naive question at all. I am facing the same problem with extracting data from COMSOL. I don't know the complete answer but I do know this: COMSOL, for some reason, plays around and shifts certain points in that fem.sol.u (perhaps to help for a more symmetric stiffness matrix). I think your best way of mapping the points back to the real space is either of the following:

1) why don't you just export the solution either in element node space, or in real symmetric cartesian space ? COMSOL can do that automatically and gives the output in a text file.

2) If not, you can get the mapping of the fem.sol.u points by calling the xmeshinfo function on the fem.xmesh (extended mesh). The output structure has a lot of info that will help you map the points back to their real space.

Sorry I realize my answer is vague but this is what I know at the moment

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