Topological Insulators: A New Platform for Fundamental Science and Applications

Topological insulators constitute a new phase of quantum matter whose recent discovery has focused world-wide attention on wide-ranging phenomena in materials driven by spin-orbit coupling effects well beyond their traditional role in determining magnetic properties. I will discuss how by exploiting electronic structure techniques we have been able to predict and understand the characteristics of many new classes of binary, ternary and quaternary topologically interesting systems. [1-4] The flexibility of chemical, structural and magnetic parameters so obtained is the key ingredient for exploring fundamental science questions, including novel spin-textures and exotic superconducting states, as well as for the realization of multi-functional topological devices for thermoelectric, spintronics, information processing and other applications. [5-7] I will also highlight new insights that have been enabled through our material-specific modeling of angle-resolved photoemission (ARPES) and scanning tunneling (STS) spectroscopies of topological surface states, including effects of the photoemission and tunneling matrix element, which is well-known to be important for a robust interpretation of various highly resolved spectroscopies. [8,9] Work supported by the Materials Science \& Engineering Division, Basic Energy Sciences, U. S. D. O. E.\\[4pt] [1] H. Lin \textit{et al.}, \textit{Nature Materials} 9, 546 (2010).\\[0pt] [2] H. Lin \textit{et al.}, \textit{Physical Review Letters} 105, 036404 (2010). \\[0pt] [3] T. H. Hsieh \textit{et al.}, \textit{Nature Communications} 3, 982 (2012). \\[0pt] [4] S. Y. Xu \textit{et al.}, \textit{Nature Communications} 3, 1192 (2012).\\[0pt] [5] S. Basak \textit{et al.}, \textit{Physical Review B-Rapid} 84, 121401 (2011).\\[0pt] [6] S-Y Xu \textit{et al.}, \textit{Nature Physics} 8, 616 (2012).\\[0pt] [7] S. Y. Xu \textit{et al.}, \textit{Science} 332, 560 (2011).\\[0pt] [8] Y. Okada \textit{et al.}, \textit{Physical Review Letters} 106, 206805 (2011).\\[0pt] [9] Y. Sakurai \textit{et al.}, \textit{Science} 332, 698 (2011).