Phonon modes and Raman intensity profiles in zinc-blende BN/GaN superlattices

By exploiting both an elastic continuum and a linear-chain model (LCM) we have systematically investigated the phonon characteristics in a series of unconventional short-period zb (BN)(m)/(GaN)(n) (001) superlattices (SLs)-selecting m or n values between 2 and 10. The calculated longitudinal folded-acoustic modes and the doublets near the phonon wavevector |(q) over right arrow (s)| are shown to have stronger dependence on the SL periods d(SL). In the framework of a bond-polarizability scheme and using a second-nearest neighbour LCM, our simulated results for the phonon dispersions and Raman intensity profiles have revealed not only the major expected trends of the vibrational characteristics observed experimentally in many conventional SLs but also elicited some interesting contrasts. We expect that the outcome of the present study will encourage experimentalists to utilize Raman scattering spectroscopy, perform material characterizations and authenticate our theoretical conjectures.