Phase diagram for magnon condensate in Yttrium Iron Garnet film. Academic Article uri icon


  • Recently, magnons, which are quasiparticles describing the collective motion of spins, were found to undergo Bose-Einstein condensation (BEC) at room temperature in films of Yttrium Iron Garnet (YIG). Unlike other quasiparticle BEC systems, this system has a spectrum with two degenerate minima, which makes it possible for the system to have two condensates in momentum space. Recent Brillouin Light Scattering studies for a microwave-pumped YIG film of thickness d = 5m and field H = 1kOe find a low-contrast interference pattern at the characteristic wavevector Q of the magnon energy minimum. In this report, we show that this modulation pattern can be quantitatively explained as due to unequal but coherent Bose-Einstein condensation of magnons into the two energy minima. Our theory predicts a transition from a high-contrast symmetric state to a low-contrast non-symmetric state on varying the d and H, and a new type of collective oscillation.

published proceedings

  • Sci Rep

author list (cited authors)

  • Li, F., Saslow, W. M., & Pokrovsky, V. L.

citation count

  • 38

complete list of authors

  • Li, Fuxiang||Saslow, Wayne M||Pokrovsky, Valery L

publication date

  • January 2013