Bhattacharya Ranjini, Maiti Santanu K
Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 Barrackpore Trunk Road, Kolkata 700 108, India.
J Phys Condens Matter. 2023 Aug 3;35(44). doi: 10.1088/1361-648X/acea4d.
Considering the unique and diverse characteristic features of antiferromagnetic (AFM) systems, here in our work, we explore spin-dependent thermoelectric behavior in an AFM ring geometry. A reasonably large (≫1) spin figure of merit, referred to as, is obtained under suitable input conditions. Two important prerequisites are (i) breaking the symmetry among up and down spin sub-Hamiltonians and (ii) generating different asymmetric transmission line shapes across a Fermi energy for two opposite spin electrons. Describing the physical system within a tight-binding framework, where spin-dependent scattering occurs due to the interaction of itinerant electrons with local magnetic moments via the usual spin-moment exchange interaction, we compute all the thermoelectric quantities based on Landauer integrals following the Green's function technique. The behavior of charge figure of merit, denoted as, is also discussed along with. Thoughreaches above unity, it is much smaller compared to. This is the key finding of our investigation. To make the present communication a self-contained one, we compare the results with another arrangement of magnetic moments in a ring-like geometry and in a chain-like one. Our analysis gives a suitable hint that in the presence of spin-dependent scattering, much more favorable energy conversion can be substantiated.
考虑到反铁磁（AFM）系统独特且多样的特征，在我们的这项工作中，我们探索了AFM环形结构中的自旋相关热电行为。在合适的输入条件下，可获得一个相当大（≫1）的自旋品质因数，记为 。两个重要的前提条件是：（i）打破向上和向下自旋子哈密顿量之间的对称性；（ii）为两个相反自旋的电子在费米能处生成不同的非对称传输线形状。在紧束缚框架内描述物理系统，其中巡游电子通过通常的自旋 - 矩交换相互作用与局域磁矩相互作用而发生自旋相关散射，我们基于格林函数技术通过朗道积分计算所有热电量。还讨论了电荷品质因数（记为 ）的行为。尽管 超过了1，但与 相比要小得多。这是我们研究的关键发现。为使本交流内容完整，我们将结果与环形和链形几何结构中磁矩的另一种排列方式进行了比较。我们的分析给出了一个合适的提示，即在存在自旋相关散射的情况下，可以证实更有利的能量转换。
