Wurtzite Effects on Spin Splitting of GaNAlN Quantum Wells.pdf

Wurtzite Effects on Spin Splitting of GaN/AlN Quantum Wells * * Ikai Lo , W. T. Wang, M. H. Gau, S. F. Tsay, and J. C. Chiang Department of Physics, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China. Abstract A new mechanism (∆C1-∆C3 coupling) is accounted for the spin splitting of wurtzite GaN, which is originated from the intrinsic wurtzite effects (band folding and structure inversion asymmetry). The band-folding effect generates two conduction bands (∆C1 and ∆C3), in which p -wave probability has tremendous change when kz approaches anti-crossing zone. The spin-splitting energy induced by the ∆C1-∆C3 coupling and wurtzite structure inversion asymmetry is much larger than that evaluated by traditional Rashba or Dresselhaus effects. When we apply the coupling to GaN/AlN quantum wells, we find that the spin-splitting energy is sensitively controllable by an electric field. Based on the mechanism, we proposed a p -wave-enhanced spin-polarized field effect transistor, made of In Ga N/In Al N, for spintronics application. x 1-x y 1-y _____________________ Keywords: GaN, Spintronics, Spin-field effect transistor, Rashba effect, Dresselhaus effect. PACS numbers: 71.15.Ap, 72.25.Dc, 73.21.Fg 1 I. Introduction Gate-controlled spin splitting in two dimensional electron system has been investigated in many zinc-blende III-V semiconductor quantum wells.1,2 The gate-controlled spin spl