论文标题
在超晶格上的自旋弗拉米式模型中的磁性顺序和传输
Magnetic order and transport in a spin-fermion model on a superlattice
论文作者
论文摘要
我们考虑了一个自旋特性模型，该模型由耦合到经典旋转的游离电子组成，后者嵌入到准一维超级晶格结构中，由由无旋转缓冲液隔开的自旋块组成。我们使用螺旋ansatz进行旋转，研究了电子介导的Ruderman-Kittel-Kasuya-Yosida（Rkky）对系统的基态状态的影响。我们发现，Rkky相互作用可以导致非系统参数的铁磁，抗铁磁或中间螺旋相。当宽度比单个块的长度大得多时，螺旋相会被抑制，并且基态在铁电磁和抗铁磁序之间振荡，因为缓冲区的大小变化。与抗磁磁性相比，这伴随着DRUDE重量的相应振荡，反映了铁磁状态的电导率增加。这些结果让人联想到经典的巨型磁化现象，在类似的薄，夹层磁性和非磁性层的几何形状中观察到。我们的分析提供了一个强大的框架，以了解Rkky相互作用在基态秩序和此类系统的相应运输特性中的作用，从而超越了常规的扰动制度。
We consider a spin-fermion model consisting of free electrons coupled to classical spins, where the latter are embedded in a quasi one-dimensional superlattice structure consisting of spin blocks separated by spinless buffers. Using a spiral ansatz for the spins, we study the effect of the electron mediated Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction on the $T=0$ ground state of the system. We find that the RKKY interaction can lead to ferromagnetic, antiferromagnetic, or intermediate spiral phases for different system parameters. When the width is much larger than the length of the individual blocks, the spiral phases are suppressed, and the ground state oscillates between ferromagnetic and antiferromagnetic order as the size of the buffer regions is varied. This is accompanied by a corresponding oscillation in the Drude weight reflecting an increased conductivity in the ferromagnetic state compared to the antiferromagnetic one. These results are reminiscent of classic giant magnetoresistance phenomena observed in a similar geometry of thin, sandwiched magnetic and non-magnetic layers. Our analysis provides a robust framework for understanding the role of the RKKY interaction on the ground state order and corresponding transport properties of such systems, extending beyond the conventional perturbative regime.
