- #1

CB4

- 10

- 0

## Homework Statement

For a lattice with a two atoms basis, the two dispersion relations valid for Ka = ±∏

w

^{2}= 2C/M

_{2}and w

^{2}= 2C/M

_{1}

Show that under these conditions the lattice acts as two independent lattices (one lattice per each atom) with one of the lattices moving while the other is at rest.

## The Attempt at a Solution

I really don't know where to begin when dealing with this problem. I presume it's dependent on an oscillatory function, but I'm completely lost as to what defines two independent lattices.