This is a type of textbook question, that means the complete answer takes more than one textbook it will depend on how much you know about electronic structure, symmetry and group theory, as well as topology.
In the forum one can answer how to do things or comment on small questions, however, why you calculated the band structure of something is a question that you have to ask yourself. In short, the irreducible representation tells you which symmetry a band has, this has mostly nothing to do with its shape. In an anylysis of the electronic structure of a semiconductor about its topological character (trivial or non trivial) you might like to check first whether band inversion occurs that is whether the energies of bands with distinguished energies are "regular" or "reversed", more details will depend on the system you are looking on, and its impossible to give here all possibilities for every crystal structiure that might occur. In certain cases you will have to check the symmetry of the bands not only at Gamma but also at other high symmetry points. Therfore, please check the textbooks and literature. Ciao Gerhard DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: "I think the problem, to be quite honest with you, is that you have never actually known what the question is." ==================================== Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz and Max Planck Institute for Chemical Physics of Solids 01187 Dresden ________________________________________ Von: wien-boun...@zeus.theochem.tuwien.ac.at [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von emami seyyed amir abbas [a.a.em...@birjand.ac.ir] Gesendet: Montag, 26. Oktober 2015 20:57 An: firstname.lastname@example.org Betreff: Re: [Wien] Band labeling Thank you very much for your helpful responds. What i realized is that for obtaining more details such as band labeling i need to run irrep. As you said for topological characterization, it is necessary to obtain band structures in irreducible representation. Is there any difference in shape of bands between normal band and ones obtained in irreducible? In other words why you mentioned it is requires to plot the bands in irreducible representations. I will be very grateful if i find my answer. Thanks _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://email@example.com/index.html