Poulsen Kasper, Zinner Nikolaj T
Department of Physics and Astronomy, Aarhus University, Ny munkegade 120, 8000 Aarhus C, Denmark.
Department of Physics and Astronomy, Aarhus University, Ny munkegade 120, 8000 Aarhus C, Denmark and Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus C, Denmark.
Phys Rev Lett. 2021 Feb 19;126(7):077203. doi: 10.1103/PhysRevLett.126.077203.
In solid state physics, giant magnetoresistance is the large change in electrical resistance due to an external magnetic field. Here we show that giant magnetoresistance is possible in a spin chain composed of weakly interacting layers of strongly coupled spins. This is found for all system sizes even down to a minimal system of four spins. The mechanism driving the effect is a mismatch in the energy spectrum resulting in spin excitations being reflected at the boundaries between layers. This mismatch, and thus the current, can be controlled by external magnetic fields resulting in giant magnetoresistance. A simple rule for determining the behavior of the spin transport under the influence of a magnetic field is presented based on the energy levels of the strongly coupled spins.
在固态物理学中，巨磁电阻是指由于外部磁场而导致的电阻大幅变化。在此我们表明，在由强耦合自旋的弱相互作用层组成的自旋链中可能存在巨磁电阻。对于所有系统尺寸，甚至小至由四个自旋组成的最小系统，都发现了这种情况。驱动该效应的机制是能谱不匹配，导致自旋激发在层间边界处被反射。这种不匹配以及电流可以通过外部磁场进行控制，从而产生巨磁电阻。基于强耦合自旋的能级，给出了一个用于确定磁场影响下自旋输运行为的简单规则。
