Behatha Anuroopa, Roy Argha Jyoti, Anusree C V, Ponvijayakanthan L, Sharma Vineet Kumar, Kanchana V
Department of Physics, Indian Institute of Technology Hyderabad, Kandi-502285, Sangareddy, Telangana, India.
J Phys Condens Matter. 2021 Apr 20;33(16). doi: 10.1088/1361-648X/abeffa.
The observation of in-plane ferromagnetism in layered magnetic materials in conjunction with the topological nodal-ring dispersion in a spin gapless semimetal with 100 % spin polarization has a fertile ground for novel physics, rich scientific significance and for the next-generation advanced spintronic and topological devices. Topological nodal ring spin gapless semimetals with large band gap in the other spin channel prevents the spin leakage and are excellent spintronic materials. On the basis of density functional theory (DFT), we have studied the layered magnetic perovskite, CsMnFwhich is predicted to be a ferromagnetic insulator though the fellow compounds likeMnF(= Na, K, Rb) are anti-ferromagnetic in nature. DFT +calculations reveal that this layered system undergoes a transition from an insulating to half-semimetallic nature with decreasing on-site Hubbard Coulomb interaction,. For= 2.5 eV, we observe the topological nature in the system with the emergence of four Mexican hat like dispersions associated with band-flipping. Also, we calculated the magneto-crystalline anisotropic energy with inclusion of spin-orbit coupling (SOC) and found that the system consists of in-plane ferromagnetism. Transport properties infer huge anisotropy of one order of magnitude between '' and '' axes. Interestingly, the estimated Fermi velocities are 2.66 × 10and 2.24 × 10m sfor(=0) and(=0.5) plane respectively and are comparable to that of graphene, which might fetch applications in high speed spin electronic devices. The topological phase observed is robust to SOC and the band-crossings associated with nodal rings could be preserved by additional symmetry as the time-reversal symmetry breaks in magnetic systems. The nearly charge compensation observed from Fermi surfaces might fetch memory device applications.
在层状磁性材料中观察到的面内铁磁性，与具有100%自旋极化的自旋无隙半金属中的拓扑节环色散相结合，为新物理、丰富的科学意义以及下一代先进的自旋电子和拓扑器件提供了肥沃的土壤。在另一个自旋通道中具有大能隙的拓扑节环自旋无隙半金属可防止自旋泄漏，是优异的自旋电子材料。基于密度泛函理论（DFT），我们研究了层状磁性钙钛矿CsMnF，尽管MnF（=Na、K、Rb）等同类化合物本质上是反铁磁性的，但预计CsMnF是一种铁磁绝缘体。DFT+计算表明，随着在位哈伯德库仑相互作用的减小，该层状体系从绝缘性质转变为半金属性质。对于=2.5 eV，我们观察到系统中的拓扑性质，出现了与能带翻转相关的四个墨西哥帽状色散。此外，我们在考虑自旋轨道耦合（SOC）的情况下计算了磁晶各向异性能，发现该系统由面内铁磁性组成。输运性质推断在“”和“”轴之间存在一个数量级巨大的各向异性。有趣的是，分别对于（=0）和（=0.5）平面，估计的费米速度为2.66×10和2.24×10 m s，与石墨烯的费米速度相当，这可能在高速自旋电子器件中得到应用。观察到的拓扑相对于SOC是稳健的，并且随着磁系统中时间反演对称性的破坏，与节环相关的能带交叉可以通过额外的对称性得以保留。从费米面观察到的近乎电荷补偿可能会带来存储器件应用。
