Theoretical Study of Neuromorphic Devices Based on Two-dimensional-based Magnetic Tunnel Junctions

基于二维磁隧道结的神经形态器件的理论研究

• 批准号: 22KJ2092
• 负责人: Harfah Halimah
• 金额: $ 1.41万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2023
• 资助国家: 日本
• 起止时间: 2023-03-08 至 2024-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-22KJ2092/
• 关键词: hexagonal boron nitride; graphene (Gr); localized state; spin coupling; vacancy; magnetic proximity; neuromorphic device; magnetoresistance (MR); proximity effect; magnetic tunnel junction; optical-based MTJ; new MTJ mechanism

To understand graphene (Gr) and hBN stability on Ni(111) substrate when a vacancy is created and their magnetic properties around the vacancy site, first-principles calculations were performed on several graphene and hBN vacancy systems as follows: 1.) Gr-vacancy/Ni; A spin-polarized localized state was observed when vacancy was created on the hollow site of Gr with a magnetic moment parallel to the neighboring C atoms, but opposite direction with Ni-slab. 2.) hBN-vacancy/Ni; A spin-polarized localized state was observed when vacancy was created on the B-site of hBN. The spin direction of a spin-polarized localized state was parallel to the N atoms surrounding the vacancy. Because of that, the spin direction of the localized state is parallel to Ni slabs creating a perfect spin filter. 3.) Gr-vacancy-hBN/Ni; Any vacancy on C atoms gives the vacancy a spin-polarized localized state with a spin direction opposite to Ni's substrate spin. Furthermore, the magnetic proximity effect from the Ni slab enables possible control of the spin direction of the localized state by controlling Ni magnetic alignment. However, when H atoms were considered at vacancy, creating V111, the H atoms preferred to buckle up, causing no spin-polarized localized state created at vacancy. From these results, a possible multi-level magnetic state can be expected by controlling the localized state spin direction of multi-stacking hBN and Gr vacancies.The importance of hybridization at the interface on affecting the proximity effect was also found when hBN/oxidized Ni surface and hBN/Ni3Au was considered.

为了理解Ni（111）底物的石墨烯（GR）和HBN稳定性，当创建空缺并在空缺位置周围的磁性特性时，对几个石墨烯和HBN空位系统进行了第一原理计算，如下所示：1。）GR-VACACANCY/NI；当在GR的空心部位创建空位，并平行于相邻C原子，但与Ni-Slab相反的方向时，观察到自旋偏振局部状态。 2.）HBN-VACANCY/NI；当在HBN的B点上产生空缺时，观察到自旋偏振局部状态。自旋偏振局部状态的自旋方向平行于空位周围的N原子。因此，局部状态的自旋方向与Ni板平行，形成了完美的自旋滤波器。 3.）gr-vacancy-hbn/ni; C原子上的任何空缺使空缺具有自旋偏振局部状态，其自旋方向与Ni的底物自旋相反。此外，NI平板的磁接近效应可以通过控制Ni磁比对来控制局部状态的自旋方向。但是，当在空位时考虑H原子时，创建V111时，H原子更喜欢屈曲，不会在空位处产生自旋极化的局部化状态。从这些结果中，可以通过控制多堆叠HBN和GR空缺的局部状态旋转方向可以预期出现多级磁态。在考虑HBN/氧化Ni表面和HBN/NI3AU时，界面上杂交对影响接近效应的重要性也被发现。

项目成果

Controlling the Gapped Dirac Cone of Graphene through Pseudospin to Achieve Colossal in-Plane Magnetoresistance

通过赝自旋控制石墨烯的有间隙狄拉克锥以实现巨大的面内磁阻

• 发表时间: 2021
• 作者: Yusuf Wicaksono;Halimah Harfah;Gagus Ketut Sunnardianto;Muhammad Aziz Majidi;and Koichi Kusakabe
• 通讯作者: and Koichi Kusakabe

Spin-Topological Electronic Valve in Ni/hBN-Graphene-hBN/Ni Magnetic Junction

• DOI: 10.3390/magnetochemistry9050113
• 发表时间: 2023-04-25
• 期刊: MAGNETOCHEMISTRY
• 影响因子: 2.7
• 作者: Wicaksono，Yusuf;Harfah，Halimah;Kusakabe，Koichi
• 通讯作者: Kusakabe，Koichi