Cover Picture: Observing electronic structures on ex-situ grown topological insulator thin films (Phys. Status Solidi RRL 1–2/2013)
S. H. Yao, B. Zhou, M. H. Lu, Z. K. Liu, Y. B. Chen, J. G. Analytis, C. Brüne, W. H. Dang, S.-K. Mo, Z.-X. Shen, I. R. Fisher, L. W. Molenkamp, H. L. Peng, Z. Hussain and Y. L. Chen
Version of Record online: 12 FEB 2013 | DOI: 10.1002/pssr.201390000
Topological insulators represent a novel state of quantum matter recently discovered with insulating bulk but conducting surface states formed by an odd number of Dirac fermions, which process helical spin texture and symbolic linear band dispersion in the momentum space. Besides their scientific significance, this class of materials has been demonstrated to be promising for numerous potential applications, such as low-power electronics, spintronic devices, and even quantum computation. The front-cover image illustrates the electronic structure of an elemental topological insulator Bi2Se3 with a single Dirac point at the apex of the conical band dispersion. This electronic structure can be directly detected by angle-resolved photoemission spectroscopy (ARPES, see the Letter by S. H. Yao et al., pp. 130–132). In addition to the conventional in-situ prepared samples within the ultra-high vacuum environment, Yao et al. recently succeeded in developing methods to obtain the band structures of ex-situ prepared topological insulators, making the study of electronic structures in many functional materials and devices a reality.