Effect of Doping Concentration and Barrier Thickness on Rashba Spin Splitting in Al0.5Ga0.5N/GaN Heterostructures

Schrodinger equation and Poisson equation are solved self-consistently for Al_0.5Ga_0.5N/GaN heterojunctions grown along the c axis, then the distribution of electrons and the exact energy of all the bounded states confined in heterojunctions are gotten, and the electrons are found to take up the first two subbands. Considerable magnitude of Rashba spin splitting for the first subband at the Fermi level is obtained. The changes of Rashba spin splitting with barrier thickness, and doping concentration in the barrier are calculated. The results show that Rashba spin splitting in Al_0.5Ga_0.5N/GaN heterojunctions increase with doping concentration and the thickness of the barrier, and the internal electric field caused by piezoelectric polarization and the spontaneous polarization is crucial for considerable Rashba spin splitting in Al_0.5Ga_0.5N/GaN heterojunctions. Therefore, we can change barrier thickness and doping concentration to modulate internal electric field and then Rashba spin splitting in Alo_0.5Ga_0.5N/GaN heterojunctions.