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_xGa_1?xN/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