Letters in 2011

The Kondo effect describes electrons scattering off a magnetic impurity, which affects the resistivity of a metal at low temperatures. In the case of buried iron or cobalt atoms, the correlations are longer ranged than studies of adatoms have shown.

Power-law scaling of critical phenomena has been most powerful for predictions near a critical point. By averaging the noise emitted by avalanches of a given duration, however, universal scaling functions can extend the predictive power of scaling far from the critical point.

Photoemission measurements sensitive to the momentum perpendicular to the layers that make up the pnictide superconductors are able to map out a full three-dimensional superconducting gap structure.

Instead of the usual chemical doping or applied pressure methods for controlling quantum phase transitions, it’s now possible to break chemical bonds to tune into a ferromagnetic quantum critical point.

Intuition suggests that the occurrence of large quantum fluctuations should prevent a material from forming a glass by enabling its atoms to rearrange into a lower-energy ordered state. But new simulations suggest the opposite could be true, with fluctuations sometimes enhancing glass formation.

A tour-de-force study finds that as the pressure of lithium is increased to 50 GPa, its melting point drops to 190 K—the lowest yet observed of any elemental metal. The results suggest lithium could be a promising candidate for exploring exotic states of matter similar to that predicted for metallic hydrogen.

A demonstration of the use of laser-driven plasma accelerators to generate electron beams having sharp temporal features of durations approaching 1 femtosecond, and currents of 3–4 kiloamperes, improves the outlook for using these devices in the development of compact free-electron lasers