We predict the presence of strong dichroic effects induced by nanoshaped x-ray beams carrying orbital angular
momentum (OAM). Taking the difference between spectra obtained with positive and negative OAM
states allows the separation of quadrupolar from dipolar transitions at, e.g., the transition-metal K edges, enabling the study of the unoccupied states in the absence of strong core-hole effects. Michel van Veenendaal and Ian McNulty, accepted Phys. Rev. Lett.
The authors report on a resistance anomaly in disordered superconducting films containing arrays of
irregularly distributed nanoscale holes. At high driving currents, peaks appear in the resistance as a
function of temperature, with peak values up to 2% above the classic normal-state resistance. J. Hua (NIU/ANL Distinguished Graduate Fellow), Z. L. Xiao, D. Rosenmann, I. Beloborodov, U. Welp, W. K. Kwok and G. W. Crabtree, Appl. Phys. Lett. 90, 072507 (2007)
We show here that the hole spin polarization and the higher-order multipoles can precess due to the valence-band spin-orbit coupling, yet in the absence of external or
effective magnetic fields. We suggest an experimental setup in which hole spin precession gives rise to an alternating spin
polarization. Dimitrie Culcer, C. Lechner, R. Winkler, Phys. Rev. Lett. 97, 106601 (2006)
