supported by the Australian Commonwealth Government.

Subtleties of bandstructure {#sec:bravais}
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Regardless of the type of calculation being undertaken, a bandstructure diagram is inherently linked to the type (shape and size) of cell being used to represent the system under consideration. For each of the 14 Bravais lattices available for three-dimensional supercells, a particular Brillouin zone (BZ) with its own set of high-symmetry points exists in reciprocal space [@Bradley72]. Similarly, each BZ has its own set of high-symmetry directions. Some of these BZs share a few high-symmetry point labels (or directions), such as $X$ or $L$ ($\Delta$ or $\Sigma$), and they all contain $\Gamma$, but these points are not always located in the same place in reciprocal space.

A simple effect of this can be seen by increasing the size of a supercell. This has the result of shrinking the BZ, and the coordinates of high-symmetry points on its boundary, by a corresponding factor. Consider the conduction band minimum (CBM) found at the $\Delta$ valley in the Si conduction band. This is commonly located at $k_{0}\sim0.85\frac{2\pi}{a}$ in the $\Delta$ direction towards $X$. Should we increase the cell by a factor of 2, the BZ will shrink (BZ$\rightarrow$BZ$^{'}$), placing the valley 