# A Break points in band structure

1. Mar 23, 2016

### chikou24i

What do we mean by break points in band structure ? and what that sentence means : "if the band index were chosen in such a way that the energies are indexed in ascending order for any k then break points would appear in the εnk vs. k plot (with n fixed) wherever two lines intersect." ?
Reference: [Jenö_Sólyom,_A._Piróth]_Fundamentals_of_the_Physics of solids Volume II, page 85

2. Mar 28, 2016

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Mar 29, 2016

### chikou24i

sorry, I didn't understand what you have said.

4. Apr 2, 2016

### paralleltransport

Maybe I'm wrong, but I think that it's trying to describe what happens when 2 bands intersect. If 2 bands intersect, and you index band 1 has the "lower energy" band, and band 2 as the higher energy band

$$\epsilon_1(k)$$ would look like a surface with sharp edges (discontinuous) for dirac cone type structures. Maybe the dirac cone is a break point?