slow blogging + pnictide fun

I'll be traveling (work + vacation), so blogging will be slow until July 15 or so.

Before I go, I wanted to point out that the plot continues to thicken regarding the pairing symmetry of the new iron pnictide superconductors. For example, this paper reports scanning SQUID microscopy on a sample of one of the compounds, with no apparent evidence for sign flips in the order parameter that you might expect if the material was, e.g., d-wave like the cuprates. In contrast, this paper argues that scanning tunneling spectroscopy data resemble d-wave expectations. This paper reports photoemission studies showing that the compounds have quite a complicated band structure and suggests that different parts of the Fermi surface may have different phenomenology. That sounds reminiscent of this theory paper, but I haven't read them in detail.