# Plane waves and sites distance in a lattice

Hi, i would ask you an opinion about a (maybe stupid) doubt.
Let us think of a 1D lattice whose sites distant from each other "a"; a plane wave
in the lattice is given by $e^{ikja}$ where k is the momentum and j an
integer label for each site. Now, we modify the lattice in this way: between sites j
and j+1 we put a distance that is a+c (instead of a). Then, what is the effect of this
alteration on the plane wave? It is right to say that the only effect is a shift in the
phase of the wave before and after the sites j,j+1?

#### Attachments

• 2fili.jpg
4.5 KB · Views: 264

no one has a little suggestion ç_ç?

Bill_K