Intrinsic Ferromagnetism in 2D FeH with a High Curie Temperature.

The rational design of ferromagnetic materials is crucial for the development of spintronic devices. Using first-principles structural search calculations, we have identified 73 two-dimensional transition metal hydrides. Some of them show interesting magnetic properties, even when combined with the characteristics of the electrides. In particular, the 3̅1 FeH monolayer is stabilized in a 1T-MoS-type structure with a local magnetic moment of 3 μ per Fe atom, whose robust ferromagnetism is attributed to the exchange interaction between neighboring Fe atoms within and between sublayers, leading to a remarkably high Curie temperature of 340 K. On the other hand, it has a large magnetic anisotropic energy and spin-polarization ratio. Interestingly, the above room-temperature ferromagnetism of the FeH monolayer is well preserved within a biaxial strain of 5%. The structure and electron property of surface-functionalized FeH are also explored. All of these interesting properties make the FeH monolayer an attractive candidate for spintronic nanodevices.