Collective Spin-Density-Wave Response Perpendicular to the Chains of the   Quasi One-Dimensional Conductor (TMTSF)2PF6
  Microwave experiments along all three directions of the spin-density-wave model compound (TMTSF)$_2$PF$_6$ reveal that the pinned mode resonance is present along the $a$ and $b^{\prime}$ axes. The collective transport is considered to be the fingerprint of the condensate. In contrast to common quasi one-dimensional models, the density wave also slides in the perpendicular $b^{\prime}$ direction. The collective response is absent along the least conducting $c^*$ direction. 
K. Petukhov M. Dressel