Reconfigurable spin tunnel diodes by doping engineering VS₂ monolayers

We propose a reconfigurable spin tunnel diode based on a small spin-gapped semiconductor (non-doped VS₂ monolayer) and semi-metallic magnets (doped VS₂ monolayer) separated by a thin insulating tunneling barrier (h-BN). By using first-principles calculations assisted by the nonequilibrium Green's function method, we have carried out a comprehensive study of spin-dependent current and spin transport properties while varying the bias. The device exhibited a magnetization-controlled diode-like behavior with forward-allowed current under antiparallel magnetizations and reverse-forbidden current under parallel magnetizations at the two electrodes. The threshold voltage is tunable by the hole doping density of VS₂ monolayers. The doping effect on VS₂ monolayers indicates that the magnetic moments, the Heisenberg exchange parameters and Curie temperatures can be monotonically reduced by a larger hole doping density. Our study on VS₂ heterostructures has presented a simple and practical device strategy with very promising applications in spintronics.