Fermi Surface for Tight Binding Models
These are Fermi surfaces for nearest neighbor tight binding models arrising from a single s-level. They were produced in Mathematica. Here is a sample code courtesy of Bradley Nartowt:

```ContourPlot3D[ -2 Cos[kx] -2 Cos[ky] -2 Cos[kz] == 2.8, {kx, -\[Pi], \[Pi]}, {ky, -\[Pi], \[Pi]}, {kz, -\[Pi], \[Pi]}]

```

Simple Cubic
E = -2 cos(kxa) -2 cos(kya) -2 cos(kza)

 Simple Cubic, E = -5 Extended Zone Simple Cubic, E = -4 Extended Zone Simple Cubic, E = -3 Extended Zone Simple Cubic, E = -2 Extended Zone Simple Cubic, E = -1 Extended Zone Simple Cubic, E = 0 Extended Zone Simple Cubic, E = 1 Extended Zone Simple Cubic, E = 2 Extended Zone Extended Zone Shifted Simple Cubic, E = 3 Extended Zone Shifted Simple Cubic, E = 4 Extended Zone Shifted Simple Cubic, E = 5 Extended Zone Shifted

Body Centered Cubic
E = -8 cos(kxa/2) cos(kya/2) cos(kza/2)

 BCC, E=-7 BCC, E=-6 BCC, E=-5 BCC, E=-4 BCC, E=-3 BCC, E=-2 BCC, E=-1 BCC, E= 0 BCC, E= 1 BCC, E= 2 BCC, E= 3 BCC, E= 4 BCC, E= 5 BCC, E= 6 BCC, E= 7

Face Centered Cubic
E = -4 cos(kxa/2) cos(kya/2) -4 cos(kya/2) cos(kza/2) -4 cos(kza/2) cos(kxa/2)

 FCC, E = -11 FCC, E = -10 FCC, E = -9 FCC, E = -8 FCC, E = -7 FCC, E = -6 FCC, E = -5 FCC, E = -4 FCC, E = -3 FCC, E = -2 FCC, E = -1 FCC, E = 0 FCC, E = 1 FCC, E = 2 FCC, E = 3 FCC, E = 3.9