Transport signature of the magnetic Berezinskii-Kosterlitz-Thouless transition

Motivated by recent experimental progress in 2D magnetism, we theoretically study spin transport in 2D easy-plane magnets at finite temperatures across the Berezinskii-Kosterlitz-Thouless (BKT) phase transition, by developing a duality mapping to the 2+1D electromagnetism with the full account of spin's finite lifetime. In particular, we find that the non-conservation of spin gives rise to a distinct signature across the BKT transition, with the spin current decaying with distance power-law (exponentially) below (above) the transition; this is detectable in the proposed experiment with NiPS3 and CrCl3.

Automated summary

Based on recent experimental progress in 2D magnetism, this theoretical study investigates spin transport in 2D easy-plane magnets at finite temperatures across the Berezinskii-Kosterlitz-Thouless (BKT) phase transition, with a duality mapping to 2+1D electromagnetism taking into account spin's finite lifetime. The non-conservation of spin is found to result in a distinct signature across the BKT transition, detectable in proposed experiments with NiPS3 and CrCl3.