Role of strain in polarization switching in semipolar InGaN/GaN quantum wells

The effect of strain on the valence-band structure of (11 2- 2) semipolar InGaN grown on GaN substrates is studied. A k·p analysis reveals that anisotropic strain in the c -plane and shear strain are crucial for deciding the ordering of the two topmost valence bands. The shear-strain deformation potential D₆ is calculated for GaN and InN using density functional theory with the Heyd-Scuseria-Ernzerhof hybrid functional [J. Heyd, G. E. Scuseria, and M. Ernzerhof, J. Chem. Phys. 124, 219906 (2006)]. Using our deformation potentials and assuming a pseudomorphically strained structure, no polarization switching is observed. We investigate the role of partial strain relaxation in the observed polarization switching.