A New Method to Calculate the Rashba Spin Splitting in Ⅲ-Nitride Heterostructures

By constructing proper basis functions,the Kane Hamiltonian is transformed to two separate Hamiltonians,and the Schr?dinger equation for conduction-band envelope functions can be obtained by eliminating the valence band components of the envelope functions.Then we decouple the up-spin and down-spin states and derive the expression for the Rashba coefficient and single-particle energy,considering the spin-orbit coupling and the nonparabolicity corrections.Finally,we calculate the Rashba spin splitting for Al_(x)Ga_(1-x)N/GaN heterostructures by using the variational method.The Rashba spin splitting calculated here is of the same order of magnitude as in other Ⅲ-Ⅴ materials,showing that the internal electric field caused by the high concentration of the 2DEG is crucial for considerable Rashba spin splitting.