Rashba Spin Splitting in the Al _0.6 Ga _0.4 N/GaN/Al _0.6 Ga _0.4 N Quantum Well With an Inserted Al _<i>x</i> Ga ₁ − _<i>x</i> N Layer

We calculate the Rashba coefficient and Rashba spin splitting for the first subband of the Al 0.6 Ga 0.4 N/GaN/Al 0.6 Ga 0.4 N quantum well (QW) with an inserted Al x Ga 1 − x N layer. The inserted Al x Ga 1 − x N layer enhances the inherent structure inversion asymmetry (SIA), increases the effective thickness of the GaN triangular potential well, as well as significantly changes the polarization electric field and the electron probability density. Due to the probability density and electric field around the left well (GaN layer) being rather high, contributions to the Rashba coefficient from the left well and the left interface are dominant. These contributions also increase with the Al concentration ( x ) in the inserted Al x Ga 1 − x N layer. The increasing polarization electric field, combined with the movement of electrons toward the left interface, collectively leads to an increase in both the Rashba coefficient and Rashba spin splitting at the Fermi level as a function of x . Our findings indicate that adding an Al x Ga 1 − x N layer can significantly enhance the Rashba coefficient and Rashba spin splitting in AlGaN/GaN QWs, providing valuable insights for the design of spintronic devices. PACS number(s): 71.70.-d , 73.21.-b , 78.30.Fs