LaOMS 2 (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, LaOMS 2 (M = Ti, V, and Cr), where a La 2 O 2 layer is sandwiched between two magnetic MS 2 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 MS 2 layer is ferromagnetic with the magnetic moment mainly contributed by the M ion and the coupling between the two MS 2 layers in one structure is negligible due to the blocking of the La 2 O 2 layer; (2) LaOMS 2 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 LaOMS 2 . Our results provide not only novel structures for practical application in spintronics, but also strategies for designing new devices.