FAQ


  • Q: Why do you sometimes show 2 pairs of images together?

    A: They are stereographic images, cross your eyes to see the 3D effects. They give you more information regular 2D images. Normally crossed-eye stereograph pictures are arranged in Left-Right or Right-Left views, and there are different ways to cross your eyes depending on the way the Left and Right views are arranged.

    It turns out that different people have different preference to cross their eyes, so we provide the stereo images in both Left-Right and Right-Left arrangement. No matter how you cross your eyes, you can always find one nice, vivid 3D image, and a strange inside-out looking 3D image that you can neglect. See Stereo3D and Java3D Fermi surface page for more information.

  • Q: Your crossed-eye stereo images are too large/small for my eyes.

    A: To help the eyes cross easier, one can make images smaller/larger by changing the resolution of the monitor higher/lower.

  • Q: Why are so many elements not linked?

    A: They are mostly non-metals or the structure of their metallic phases are too complicated. Only metals have Fermi surfaces.

  • Q: What do the colors mean?

    A: Fermi surfaces of different bands are shown with different colors. For the same color, the bright side faces the higher energy volumn.

  • Q: Why do you use CMY instead of RGB color scheme?

    A: Due to the limitation of many stereographic hardwares, high brightness contrast often give ghost images. To reduce this effect, we choose colors with smaller brightness contrast.

  • Q: Are these theorectical or experiment data?

    A: The Fermi surface on our site are found by theories. Some experimentalists have measured some Fermi surfaces using techniques like angle resolved photo emission. Usually Fermi surfaces in experiments not as sharp because of the resolutions.

  • Q: How do I use your data in my own calculation?

    A: The coordinates of the Fermi surfaces are contained in each VRML 1.0 (*.wrl) file. These files are gzipped.

    For exampe:

  • download the file of interest, e.g. http://www.phys.ufl.edu/fermisurface/vrml1/Fe_bcc4.wrl

    Some VRML browsers do not allow saving, in this case, try to switch it off, or use a text based browser like Lynx, or refer to site download instructions (very large files).

  • change its name to Fe_bcc4.wrl.gz and unzip it.
  • In the ASCII file named Fe_bcc4.wrl, look for the first keyword 'Coordinate3'. Its format is { point [ x1 y1 z1, x2 y2 z2, ... ]}. These are coordinates of the points on the Fermi surface.
  • Look for the keyword 'IndexedFaceSet', which tells how to draw triangles using the above set of points.
  • Other information contained in the file are: Normal at each point, and the line and vertices of the first Brillouin zone.
  • See manual of VRML 1.0 (VRML 95) for more detail.
  • Note: the energy E(kx,ky,kz) data was too huge and were deleted once we obtain the Fermi surface. < /li>