Discovery of new class of topological material with potential for next-generation low-energy-consumption information devices
Under the leadership of SATO Takafumi , Associate Professor, Graduate School of Science, Tohoku University, ANDO Yoichi , Professor, Institute of Scientific and Industrial Research, Osaka University, and TAKAHASHI Takashi , Professor, Advanced Institute for Materials Research, Tohoku University, a group of researchers have clarified that semi-conductor SnTe (tin telluride), that has been studied for more than 40 years, is a totally new type of topological material. This research findings are expected to contribute to spintronic material technology for next-generation power-saving electronic devices and their industrialization.
Abstract
" A topological insulator is an unusual quantum state of matter, characterized by the appearance, at its edges or on its surface, of a gapless metallic state that is protected by time-reversal symmetry. The discovery of topological insulators has stimulated the search for other topological states protected by other symmetries, such as the recently predicted topological crystalline insulator (TCI) in which the metallic surface states are protected by the mirror symmetry of the crystal. In this work, we obtained experimental evidence for the TCI phase in tin telluride (SnTe), which has been predicted to be a TCI in a recent theoretical work. Our angle-resolved photoemission spectra show the signature of a metallic Dirac-cone surface band, with its Dirac point slightly away from the edge of the surface Brillouin zone in SnTe. Such a gapless surface state is absent in a cousin material, lead telluride, in line with the theoretical prediction. This discovery experimentally establishes the TCI phase in SnTe and suggests the existence of many more kinds of topological material. "
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To read the full research report entitled " Experimental realization of a topological crystalline insulator in SnTe , " please go to this page at the Nature Physics website.
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