Researchers at the University of Maryland and the NIST Center for Nanoscale Science and Technology (both in US) have for the first time experimentally demonstrated surface-only charge conduction in a topological insulator [1], and have theoretically explained the conduction using techniques previously applied successfully to the understanding of graphene [2]. The research team found that the thin Bi2Se3 crystals studied have unusual magneto-electronic properties that should allow such topological insulators to be used in new types of devices, including high-performance transistors, magnetic sensors, and optical detectors.

[1] Dohun Kim, Sungjae Cho, Nicholas P. Butch, Paul Syers, Kevin Kirshenbaum, Shaffique Adam, Johnpierre Paglione, Michael S. Fuhrer: Surface conduction of topolo- gical Dirac electrons in bulk insulating Bi2Se3, In: Nature Physics, Vol. 8(2012), No. 6, June 2012, Pages 460-464, DOI:10.1038/nphys2286: http://dx.doi.org/10.1038/nphys2286

[2] S. Adam, E. H. Hwang, and S. Das Sarma: Two-dimensional transport and screening in topological insulator surface states, In: Physical Review B, Volume 85, Issue 23, June 15, 2012, Article 235413 [5 pages], DOI:10.1103/ PhysRevB.85.235413:

http://dx.doi.org/10.1103/PhysRevB.85.235413

Researchers at Cambridge University (UK) report a way to make artificial nacre for the first time using CaCO3 as the main component. The new method could lead to tough coatings from inexpensive starting materials.

Alexander Finnemore, Pedro Cunha, Tamaryn Shean, Silvia Vignolini, Stefan Guldin, Michelle Oyen, Ullrich Steiner: Biomimetic layer-by-layer assembly of artificial nacre, In: Nature Communications, Vol. 3, July 24, 2012, Article number 966, DOI:10.1038/ncomms1970: http://dx.doi.org/10.1038/ncomms1970

Researchers from the University of Toronto (U of T) and King Abdullah University of Science & Technology (KAUST) have made a breakthrough in the development of colloidal quantum dot (CQD) films, leading to the most efficient CQD solar cell ever. The U of T cell represents a 37% increase in efficiency over the previous certified record. In order to improve efficiency, the researchers needed a way to both reduce the number of “traps” for electrons associated with poor surface quality while simultaneously ensuring their films were very dense to absorb as much light as possible. The solution was a so-called “hybrid passivation” scheme.

Alexander H. Ip et al.: Hybrid passivated colloidal quantum dot solids, In: Nature Nanotechnology AOP, July 29, 2012, DOI: 10.1038/nnano.2012.127: http://dx.doi.org/10.1038/nnano.2012.127