Suppressing effective magnetic field and spin-relaxation rate by tuning barrier compositions in a (111) quantum well

Adjusting compositions of two barriers forming a (111)-oriented InGaAs/AlGaAsSb quantum well (QW) is proposed as a method to eliminate the effective magnetic field due to the Rashba and linear-in-momentum Dresselhaus spin-orbit interactions in the zeroth and first orders in the gate electric field. The resulting suppressed Dyakonov-Perel spin relaxation is used to achieve a high on/off ratio of the spin-relaxation rate at room temperature in a double-QW structure.