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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

基本信息

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

项目摘要

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.

为了了解空位产生时石墨烯 (Gr) 和 hBN 在 Ni(111) 基底上的稳定性及其空位周围的磁性，对几种石墨烯和 hBN 空位系统进行了第一性原理计算，如下所示： 1.) Gr-空位/Ni；当在 Gr 的空位上产生空位时，观察到自旋极化局域态，其磁矩平行于相邻的 C 原子，但与 Ni 板的方向相反。 2.) hBN-空位/Ni；当 hBN 的 B 位上产生空位时，观察到自旋极化局域态。自旋极化局域态的自旋方向平行于空位周围的N原子。因此，局域态的自旋方向与镍板平行，从而形成完美的自旋滤波器。 3.) Gr-空位-hBN/Ni； C 原子上的任何空位都会赋予空位自旋极化局域态，其自旋方向与 Ni 的衬底自旋相反。此外，Ni板的磁邻近效应使得可以通过控制Ni磁取向来控制局域态的自旋方向。然而，当 H 原子被认为处于空位时，产生 V111，H 原子倾向于弯曲，导致空位处不会产生自旋极化局域态。从这些结果中，通过控制多层六方氮化硼和Gr空位的局域态自旋方向，可以预期可能的多级磁态。当考虑六方氮化硼/氧化Ni表面和六方氮化硼/Ni3Au表面时，还发现界面杂化对影响邻近效应的重要性。