I have a cubic-FCC with a=b=c and $\alpha$=$\beta$=$\gamma$=$90^o$. As far as I understand the volume of this cubic unit cell should be a cube of the lattice constant. But this not the case I am seeing in the quantum ESPRESSO, SCF output file:
bravais-lattice index = 2 lattice parameter (alat) = 10.9569 a.u. unit-cell volume = 328.8522 (a.u.)^3 number of atoms/cell = 4 number of atomic types = 3 number of electrons = 60.00 number of Kohn-Sham states= 36 kinetic-energy cutoff = 200.0000 Ry charge density cutoff = 2000.0000 Ry
As you can see that unit cell volume is not the cube of the lattice parameter. Why is it so? Am I putting any parameter wrongly?
Please help with this.