[xcrysden] 2D cuts of the Fermi surface

[Tone Kokalj]

On Tue, 2006-02-14 at 10:42 -0800, Suman Hossain wrote:
> Dear Xcrysden Community,
> 
> I've been using the nice Xcrysden Fermi surface viewer for a while
> which is absolutely fantastic. It is meant to generate 3D surfaces.
> But now I need to make certain 2D cuts of the Fermi surface I already  
> made.

Unfortunately, xcrysden does not yet have this feature. 

But it would be possible to emulate it with some manual work: extract
the correct slice from the 3D mesh and pretend you will plot something
like charge density: i.e. in XSF file make a 2D DATAGRID instead of 3D
BANDGRID. 

Note that XSF file should include at least one dummy atom.
Then load the XSF file, switch off the display of atoms, and use the Tools->Data Grid menu.
 From this point on you pretend to render charge density: 
you have all the xcrysden contour features at disposal.

The proper XSF should look as:

SLAB
PRIMVEC
ax ay 0.0
bx by 0.0
0.0 0.0 1.0

PRIMCOORD
1 1
X 0.0 0.0 0.0

BEGIN_BLOCK_DATAGRID_2D
a_sheet_of_eigenvalues
DATAGRID_2D_bla_bla
nx ny
0.0 0.0 0.0
ax ay 0.0
bx by 0.0
-8.632000e-11 -1.614379e-10 -2.793978e-10 
-4.472420e-10 -6.637130e-10 -9.109040e-10 -1.153951e-09  
... (nx * ny values here)
END_DATAGRID_2D
END_BLOCK_DATAGRID_2D

I guess it is clear what the ax, ay, bx, by, nx, and nz stand for, otherwise look at the XSF format specification
( http://www.xcrysden.org/doc/XSF.html#__toc__11 )

Regards, Tone