Polarization anisotropy in semiconductor nanowires is studied using the standard eight-band $\mathbf{k}\bullet \mathbf{p}$ theory. We show that the anisotropy ratio ranges from giant $(\sim 90\%)$ to moderate $(\sim 60\%)$ for the nanowire radius between 3 and 10 nm. Our result resolves an apparent contradiction between a recent tight-binding study [M. P. Persson and H. Q. Xu, Phys. Rev. B 70, 161310(R) (2004)], which predicts 100% anisotropy, and an earlier $\mathbf{k}\bullet \mathbf{p}$ study [P. C. Sercel and K. J. Vahala, Phys. Rev. B 44, 5681 (1991)], which predicts 60% anisotropy independent of radius. We show that with proper inclusion of band mixing, the $\mathbf{k}\bullet \mathbf{p}$ theory agrees well with the tight-binding study on anisotropy.

• Received 12 May 2005

DOI:https://doi.org/10.1103/PhysRevB.72.161310