+ \item \begin{minipage}{0.5\textwidth}
+ $m_n=m_p$:\\
+ \includegraphics[width=5cm,angle=-90]{dos_is_1.eps}
+ \includegraphics[width=5cm,angle=-90]{fermi_1.eps}
+ \includegraphics[width=5cm,angle=-90]{ccc_1.eps}
+ \end{minipage}
+ \begin{minipage}{0.5\textwidth}
+ $m_n \ne m_p$:\\
+ \includegraphics[width=5cm,angle=-90]{dos_is_2.eps}
+ \includegraphics[width=5cm,angle=-90]{fermi_2.eps}
+ \includegraphics[width=5cm,angle=-90]{ccc_2.eps}
+ \end{minipage}