Rashba effect in type-II resonant tunneling diodes enhanced by in-plane magnetic fields

Abstract

In this paper, we adapt the transfer matrix method to calculate the current-voltage curves of type-II GaAsSb/InGaAs resonant tunneling diodes on which a huge Rashba splitting of the current resonances has been reported recently. It is shown that, in transverse magnetic fields, the ${k}_{\ensuremath{\parallel}}$ distribution of tunneling electrons is shifted to higher values. Through this process, a significant asymmetry is induced in the tunneling structure, which finally leads to a strong enhancement of the Rashba effect. Further, we find that the Rashba effect is extremely sensitive to the electric fields produced by the band discontinuities at the heterostructure interfaces and to the spin-orbit coupling constants in the respective materials. Using a one-band model for the spin-orbit coupling constant, the effects of temperature and local electric fields on the Rashba parameter are also investigated. From our findings, we conclude that spin-splitting effects and large spin-orbit interactions should be quite dominant in any narrow-gap type-II heterostructure, and not only in the GaAsSb/InGaAs material system.