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.