Magnon-assisted tunnelling in van der Waals heterostructures based on CrBr3
Magnon-assisted tunnelling in van der Waals heterostructures based on CrBr3
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DOI：
10.1038/s41928-018-0087-z
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发表时间：
2018-06-01
影响因子：
34.3
通讯作者：
Misra, A.
中科院分区：
文献类型：
--
作者：
Ghazaryan, D.;Greenaway, M. T.;Misra, A.
货车瓦异质结构是由二维层状材料组成的，它为研究各种物理现象提供了一个平台，并可用于各种应用。最近报道了含有二维铁磁体的异质结构，例如三碘化铬（CrI3），这可以允许开发二维自旋电子器件。在这里，我们研究隧穿通过薄铁磁三溴化铬（CrBr3）的障碍，夹在石墨烯电极之间。在具有非磁性势垒的器件中，动量守恒可以通过声子辅助隧穿或通过局域态隧穿来放松。相比之下，在具有铁磁势垒的器件中，主要的隧穿机制是低温下的磁振子发射和居里温度以上的温度下的电子在局部磁激发上的散射。石墨烯电极中的磁阻进一步表明通过铁磁势垒诱导的自旋轨道耦合和邻近交换。磁振子发射的隧道效应提供了自旋注入的可能性。
Van der Waals heterostructures, which are composed of layered two-dimensional materials, offer a platform to investigate a diverse range of physical phenomena and could be of use in a variety of applications. Heterostructures containing two-dimensional ferromagnets, such as chromium triiodide (CrI3), have recently been reported, which could allow two-dimensional spintronic devices to be developed. Here we study tunnelling through thin ferromagnetic chromium tribromide (CrBr3) barriers that are sandwiched between graphene electrodes. In devices with non-magnetic barriers, conservation of momentum can be relaxed by phonon-assisted tunnelling or by tunnelling through localized states. In contrast, in the devices with ferromagnetic barriers, the major tunnelling mechanisms are the emission of magnons at low temperatures and the scattering of electrons on localized magnetic excitations at temperatures above the Curie temperature. Magnetoresistance in the graphene electrodes further suggests induced spin-orbit coupling and proximity exchange via the ferromagnetic barrier. Tunnelling with magnon emission offers the possibility of spin injection.