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Center for Nonlinear Studies |
The paradigm mixed valence insulator SmB6, exhibits a mysterious residual metallic conductivity at low temperatures (T < 4 K) [1], with a value too small to explain within the framework of three-dimensional extrinsic [1] or intrinsic [2] bulk conduction scenarios. Over time all efforts to eliminate this residual conductivity have failed. It has recently been shown that the symmetry requirements for a bulk single particle gap in SmB6 [3] also satisfy the requirements for the protected surface states of a topological insulator (TI) [4-6]. I will describe transport [7], de Haas van Alphen [8] and angle resolved photoemission spectroscopy [9] experiments, and as time permits other work, all showing that SmB6 is indeed a TI material. These new findings resolve in an elegant way the 30 year old transport mystery of SmB6, provide a material in which the dc transport properties of a 3D topological state can be directly studied, and generally highlight the promise for further exploration of topological symmetries in strongly correlated electron materials.
* Collaboration with J. D. Denlinger, Z. Fisk, J.-S. Kang, D.-J. Kim, Ç. Kurdak, Lu Li, B. I. Min, K. Sun, and S. Wolgast
Host: Eric Bauer