Ferroelectricity from spin supercurrents in LiCuVO4
  We have studied the magnetic structure of the ferroelectric frustrated spin-1/2 chain material LiCuVO4 in applied electric and magnetic fields using polarized neutrons. A symmetry and mean-field analysis of the data rules out the presence of static Dzyaloshinskii-Moriya interaction, while exchange striction is shown to be negligible by our specific-heat measurements. The experimentally observed magnetoelectric coupling is in excellent agreement with the predictions of a purely electronic mechanism based on spin supercurrents. 
M. Mourigal, M. Enderle, R. K. Kremer, J. M. Law, B. F{\aa}k
cond-mat.str-el cond-mat.mtrl-sci