Editor's Summary
24 April 2008
The best of both worlds
Two of the hottest topics in fundamental condensed matter physics are relativistic Dirac particles and the quantum spin Hall phase. Materials that realize either one of these phenomena are scarce, but new work in bismuth-antimony crystals points to a novel state of quantum matter with both properties. Dirac particles have so far been discovered only in graphene, and the topological edge states central to the quantum spin Hall phase have yet to be directly observed. Hsieh et al. now show, through experimental observation of the simple crystal system Bi1- xSbx, that the three-dimensional generalization of both these exotic quantum phases coexist and are highly coupled. This 'topological metal' could be of interest for developing next-generation quantum computing devices.
Letter: A topological Dirac insulator in a quantum spin Hall phase
D. Hsieh, D. Qian, L. Wray, Y. Xia, Y. S. Hor, R. J. Cava & M. Z. Hasan
doi:10.1038/nature06843
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