2004/05/27 by D. Schmeltzer, A. Saxena, Schmeltzer, D. +5
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0405659
14 pages plus one figure
arxiv created 2004/05/27 · arxiv updated 2009/12/01
We show that a spatially-dependent magnetic field can induce a persistent spin current in a spin-1/2 Heisenberg antiferromagnetic ring, proportional to the solid angle subtended by the magnetic field on a unit sphere. The result is a direct consequence of Berry "parallel transport" in space. The magnitude of the spin current is determined by the ratio of longitudinal and transverse exchange interactions J_∥/J_⊥ and by the magnetic field. For large magnetic fields the Zeeman energy strongly renormalizes the Ising term giving rise to a maximum spin current. In the limit of J_∥/J_⊥≪1 the amplitude of the current behaves like 1-(J_∥/J_⊥)2. In the opposite limit πJ_⊥> J_∥>J_⊥ the amplitude scales as √(J_∥/ J_⊥)exp(-√(J_∥/J_⊥)).