LaOMS₂ (M = Ti, V, and Cr): novel crystal spin valves without contact

2D materials are widely investigated for application in nanodevices and spintronics. Here, we demonstrate that a family of structures, LaOMS₂ (M = Ti, V, and Cr), where a La₂O₂ layer is sandwiched between two magnetic MS₂ layers, are suitable to be used as spin valves without contact. We show that they are stable and exhibit unique magnetic and electronic properties. We find that (1) each MS₂ layer is ferromagnetic with the magnetic moment mainly contributed by the M ion and the coupling between the two MS₂ layers in one structure is negligible due to the blocking of the La₂O₂ layer; (2) LaOMS₂ can be a half-metal in the ferromagnetic (FM) state and a conductor in the interlayer antiferromagnetic (inter-AFM) state, and the total energies of the two states are almost identical; (3) the magnetic properties and exchange energy can be effectively controlled by contacting with other materials; and (4) a 100% spin current is achieved in FM LaOMS₂. Our results provide not only novel structures for practical application in spintronics, but also strategies for designing new devices.