Antiferromagnet — Magnon Spin Seebeck Effect
Thermal gradient drives spin current via two-sublattice magnon dispersions in antiferromagnets
Magnetic Parameters
Exchange J (meV):
10
Anisotropy K (meV):
0.5
External field H (T):
0.0
Temperature Gradient
Temperature T (K):
100
∇T (K/mm):
5.0
g
μB
μ₀H energy: Zeeman split
Spin Seebeck coeff:
S
SE
= ∫ τ(ω)·ω·∂f/∂T dω
f: Bose-Einstein distribution
Theory
AFM two-mode dispersion:
ω±(k) = √(ω_ex²(1−cos²(ka)) + ω_A²) ± ω_H
ω_ex = zJS/ℏ (exchange freq.)
ω_A = √(2KJS)/ℏ (anisotropy gap)
ω_H = gμ_B·H/ℏ (Zeeman split)
Two modes carry opposite spin ±ℏ
Temperature gradient → mode imbalance
→ net spin current J_s = ∫(f+ − f−)·v·τ