Tunable charge and spin beams in RuS4 monolayer

The recently predicted penta-RuS₄ monolayer with high stability, large nontrivial band gap and robustness against oxidation is promising for applications in nanoelectronics. The band structure of this material exhibits unique characteristics under the uniaxial strains and we show that this feature provides the possibility of generating the controllable charge and spin beams. We calculate the transport coefficients for the strain barrier in this monolayer, generally, in the presence of a magnetic filed and an applied voltage. Charge transport through the strain barrier shows that we can generate electron beams which their directions are adjusted by the strain and the external voltage. Also, we show that by addition of a magnetic field, we can generate fully spin polarized electron beams, emerging at angles determined by the applied voltage. These features can be of great importance in designing splitters and spin lenses. The possibility of changing the perfect polarizations between the two spin states, easily by altering the voltage, highlights the potential application of RuS₄ monolayer for spintronic switches. Our calculations demonstrate that for the very small lengths of the strain barrier, the tunneling effect of evanescent waves dominates the contributions of the itinerant waves in transport process. We show that this unique phenomenon is related to the shape of the band structure.