deletions | additions       diff --git a/section_Topological_Insulators.tex b/section_Topological_Insulators.tex  index 08eb120..474f236 100644  --- a/section_Topological_Insulators.tex  +++ b/section_Topological_Insulators.tex 
...
For topological insulators like HgTe/CdTe quantum wells, effective energy dispersions have been found to represent the bands of interest using a two band model.  \begin{equation}  E\pm=d E\pm=\epsilon(k)\pm \sqrt{A^2(kx^2+ky^2)+M^2}  \end{equation}