Introductions to the Focus stories of the past week;
visit http://focus.aps.org for the complete stories.

A NEW SOURCE OF SPIN CONTROL
Electrons are underappreciated. Every electronic device depends on
the electron's charge, but few gadgets acknowledge--much less
exploit--its property of spin. Researchers in the field of
spintronics are developing devices that use "spin polarized"
electric currents--currents dominated by either spin up or spin down
electrons. Now a team reports in the 7 May PRL that they can
generate such currents simply by shining light on the right
material. They show that in a broad class of nanostructures,
circularly polarized light creates a spin polarized current. The
technique may help researchers learn more about spin-based effects
and could also lead to a new detector for circularly polarized
light.
(S. D. Ganichev et al., Phys. Rev. Lett. 86, 4358.
Link to the paper: http://link.aps.org/abstract/PRL/v86/p4358/
COMPLETE Focus story at http://focus.aps.org/v7/st21.html)

Also from the current PRL (story from AIP's Physics News Update):

ULTRASONIC BANDGAP MATERIALS
Story at http://www.aip.org/physnews/update/536-1.html
(M. Torres et al., Phys. Rev. Lett. 86, 4282)