Plotting band-decomposed charge density (CBM/VBM) for 2D Janus monolayer

Chhatra

Dear Crystal Users and Developers,

I am currently studying the electronic properties of a 2D Janus monolayer, using CRYSTAL17. I am interested in visualizing the spatial localization of the Valence Band Maximum (VBM) and Conduction Band Minimum (CBM) to confirm charge separation across the Janus surfaces.
My system is a semiconductor with a direct band gap at the
K point. I would like to generate 3D electron density maps (isosurfaces) for these specific bands only.

Any guidance or example .d3 inputs for band-specific density plotting would be greatly appreciated.
Thank you for your time and help.

Best regards,
Chhatra Subba

aerba

Hi,

You can do this using the PROPERTIES module. The PBAN option [see CRYSTAL23 User's Manual at page 348] allows you to build a density matrix from a user-defined subset of electronic bands. This partial density matrix is used for subsequent calculations. The ECH3 option can then be used to evaluate the associated electron density on a user-defined 3D grid of points, to be stored in .cube format, which can then be plotted in 3D isosurfaces with standard visualizers, such as VESTA.

A template .d3 PROPERTIES input file for this would look something like:

NOSYMADA
NEWK
24 24
1 0
PBAN
1
14
ECH3
80
RANGE
-10 10
END

where in PBAN as an example I have selected just 1 band, number 14 in the list.

Hope this helps,

Chhatra

Thank you so much! I'll give this a try; it helps a lot.

Chhatra

Thank you very much for your previous help — the method works perfectly for the valence band.

However, I’m encountering an issue when trying to plot the partial electron density for the conduction band. It does not seem to return any values, possibly because those bands are unoccupied.

I was wondering if there is an alternative way to analyze the conduction band states — for example, accessing the corresponding wavefunctions or something analogous to HOMO/LUMO analysis in molecular codes like Gaussian.

Any guidance or suggestions would be greatly appreciated.

Thank you in advance!

aerba

Hi,

To analyze conduction bands I can recommend a couple of options:

Decomposition of selected bands into leading AO contributions. This option allows to characterize the nature of a band at a given k point in terms of the main AOs contributing to it. From the PROPERTIES module, refer to the ANBD keyword, see page 307 of the User's Manual.
3D plotting of crystalline orbitals. From the PROPERTIES module, refer to the ORBITALS keyword, see page 347 of the User's Manual.

Hope this helps,

Chhatra

Thank you so much!