Effect of well thickness on the Rashba spin splitting and intersubband spin–orbit coupling in AlGaN/GaN/AlGaN quantum wells with two subbands

Abstract

By projecting the characteristic equation into the subspace of the conduction band, the Rashba spin splitting coefficient for the first two subbands ( α 1 , α 2 ) and the intersubband spin–orbit coupling coefficient ( η 12 ) in AlGaN/GaN quantum well structure are obtained. Then sizable α 1 , α 2 and η 12 in QWs are calculated by solving the Schrödinger and Poisson equations self-consistently. We find that the internal electric field is crucial for considerable spin–orbit coupling effect in III-nitride QWs and the spin–orbit coupling coefficient can be greatly modulated by the well thickness. Compared with the Rashba coefficient, the intersubband spin–orbit coupling coefficient is basically of the same order of magnitude. The results show the great possibility of spin manipulation in low-dimensional semiconductors, and III-nitride QWs are candidates for the design of spintronic devices.