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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.

为了了解石墨烯（Gr）和hBN在Ni（111）衬底上产生空位时的稳定性以及它们在空位位置周围的磁性，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：Gr-vacancy /镍;在与相邻的C原子方向相反的磁矩方向上，在Gr的空心位置产生空位，观察到自旋极化局域态。2) hBN-vacancy /镍;当hBN的b位产生空位时，观察到自旋极化局域态。自旋极化局域态的自旋方向与空位周围的N原子平行。因此，局域态的自旋方向与Ni板平行，形成了一个完美的自旋过滤器。3.） Gr-vacancy-hBN /镍;C原子上的任何空位都具有自旋极化局域态，自旋方向与Ni的底物自旋方向相反。此外，来自Ni板的磁邻近效应使得通过控制Ni的磁排列来控制局域态的自旋方向成为可能。然而，当H原子处于空位时，产生V111， H原子倾向于扣紧，导致在空位处没有产生自旋极化的局域态。根据这些结果，可以通过控制多层hBN和Gr空位的局域态自旋方向来实现多层磁态的可能性。当考虑hBN/氧化Ni表面和hBN/Ni3Au时，也发现了界面杂化对接近效应的重要影响。