论文标题
NM/NM/FI异质结构中镁介导的自旋转运的普遍行为
Universal behavior of magnon-mediated spin transport in disordered NM/NM/FI heterostructure
论文作者
论文摘要
在安德森（Anderson）疾病的存在下，我们在数值上研究了非磁性金属/非磁性金属/铁磁绝缘子（NM/NM/FI）异质结构的镁介导的自旋传输和缩放行为。对于二维（2D）NM/NM/FI系统，由于NM/FI界面处的状态界面密度（DOS）的增加，因此发现了弱混乱状态中自旋电导的增强。结果，在金属状态下发现了新的缩放机制，其中自旋电导波动RMS（G）与平均自旋电导<G>线性缩放，与Fermi Energies和温度等系统参数无关。疾病增强的界面DOS与被无序的自旋转运之间的竞争导致平均旋转电导对疾病强度的非单调依赖性。在本地化方案中，不同系统参数的LNG的方差遵循了一个通用函数，该功能取决于旋转电导的对数<lng>的平均值。局部状态中LNG的分布是非高斯的，其与高斯的偏差可以以第三和第四级的累积累积的累积累积的lng，lng，k3和k3和k3和k3和k3和k3和k3和k3和k3 and k3和k4。我们发现K3〜 <-lng>^3/2和K4〜 <lng>^2。这表明由NM/NM/FI混合系统中的木纳介导的自旋电导属于不同的通用类别。对于固定的<lng>，发现不同系统参数的局部状态中的LNG分布会崩溃到单个曲线上，这表明分布p（lng; <lng>）是一个普遍的函数，仅取决于<lng>。此外，研究了疾病存在下的自旋热电器S，并发现LNS的方差与<lns>在局部状态中的不同系统参数中线性扩展。还研究了1D nm/nm/FI的自旋电导和自旋热电器。
We numerically investigate the magnon-mediated spin transport and scaling behaviors of a nonmagnetic metal/nonmagnetic metal/ferromagnetic insulator (NM/NM/FI) heterostructure in the presence of Anderson disorders. For the two-dimensional (2D) NM/NM/FI system, an enhancement of spin conductance in the weak disorder regime is found due to the increasing of the interfacial density of states (DOS) at NM/FI interface. As a result, a new scaling regime is uncovered in the metallic regime where the spin conductance fluctuation rms(G) scales linearly with the average spin conductance <G>, independent of system parameters such as Fermi energies and temperatures. The competition between the disorder-enhanced interfacial DOS and disorder-suppressed spin transport results in a non-monotonic dependence of average spin conductance on disorder strength. In the localized regime, the variance of lnG for different system parameters follows a universal function that depends linearly on the average of logarithm of spin conductance <lnG>.The distribution of lnG in the localized regime is non-Gaussian whose deviation from Gaussian can be characterized by the third and fourth order cumulants of lnG, denoted as k3 and k4, respectively. We find that k3~<-lnG>^3/2 and k4~<lnG>^2. This suggests that the spin conductance mediated by magnon in NM/NM/FI hybrid systems belongs to a different universality class. For fixed <lnG>, the lnG distribution in the localized regime for different system parameters is found to collapse onto a single curve, suggesting the distribution P(lnG;<lnG>) is a universal function that depends only on <lnG>. Furthermore, spin thermopower S in the presence of disorder is studied and the variance of lnS is found to scale linearly with <lnS> for different system parameters in the localized regime. Spin conductance and spin thermopower for 1D NM/NM/FI are also studied.
