论文标题
三维抗铁磁铁中的自旋和热传输和关键现象
Spin and thermal transport and critical phenomena in three-dimensional antiferromagnets
论文作者
论文摘要
我们通过数值分析Cubic晶格上的经典反铁磁性$ XXZ $模型来研究Néel过渡温度附近的旋转和热传输，$ t_n $在三个维度上进行了研究，在模型中，交换互动的各向异性$δ= j_z/j_x $可以控制转移阶级的角色。它是通过混合蒙特卡洛和自旋动力学模拟找到的，在$ xy $和海森伯格的情况下，$δ\ leq 1 $，纵向自旋电导率$σ^s_ {μμμ} $在冷却方面增强了对$ t_n $的发散增强，而不是在$ t_n $中，而不是$ $Δ> $Δ在所有三种情况下，热导率的温度依赖性$κ_{μμ} $在$ t_n $时均无特征，与实验结果一致。 $σ^s_ {μμ} $对$ t_n $的发散增强归因于旋转 - 电流放松时间，该松弛时间更长，它变为$ t_n $，显示了关键现象的幂律分歧特征。还发现，与$σ^s_ {s_ {μμ} $中的差异相比，在$σ^s_ {μμ} $中迅速抑制了$ t_n $，$σ^s_ {μμμ} $，甚至可能在Heisenberg情况下仍然在$ t_n $以下发散，在Heisenberg情况下，在实验中可能会在实验中观察到理想的Isotropic $ $ nmbmn。
We investigate spin and thermal transport near the Néel transition temperature $T_N$ in three dimensions, by numerically analyzing the classical antiferromagnetic $XXZ$ model on the cubic lattice, where in the model, the anisotropy of the exchange interaction $Δ=J_z/J_x$ plays a role to control the universality class of the transition. It is found by means of the hybrid Monte-Carlo and spin-dynamics simulations that in the $XY$ and Heisenberg cases of $Δ\leq 1$, the longitudinal spin conductivity $σ^s_{μμ}$ exhibits a divergent enhancement on cooling toward $T_N$, while not in the Ising case of $Δ>1$. In all the three cases, the temperature dependence of the thermal conductivity $κ_{μμ}$ is featureless at $T_N$, being consistent with experimental results. The divergent enhancement of $σ^s_{μμ}$ toward $T_N$ is attributed to the spin-current relaxation time which gets longer toward $T_N$, showing a power-law divergence characteristic of critical phenomena. It is also found that in contrast to the $XY$ case where the divergence in $σ^s_{μμ}$ is rapidly suppressed below $T_N$, $σ^s_{μμ}$ likely remains divergent even below $T_N$ in the Heisenberg case, which might experimentally be observed in the ideally isotropic antiferromagnet RbMnF$_3$.
