Impact of interfacial thickness on Raman intensity profiles and phonon anisotropy in short-period (AlSb)n/(GaSb)m superlattices

Comprehensive simulations of phonon dispersions omega(j) (q(SL)) and atomic displacements are reported for short-period (AlSb)(n)/(GaSb)(m) superlattices (SLs) using a modified linear-chain model. A bond-polarizability methodology is employed for exploring the impact of meticulously included interfacial thickness delta (equivalent to 1-3 monolayers) on the Raman intensity profiles of graded SLs in the optical phonon region. Results of omega(j) (q(SL)) are also presented by exploiting a realistic rigid-ion-model (RIM) and considering short-range, long-range Coulomb interactions and SL symmetry. Besides the anisotropic behavior of optical phonons, the RIM provided evidence of the acoustic-mode anticrossing, minigap formation, confinement, and interface modes. Controlling the vibrational traits by altering a number of monolayers (n, m) in SLs can provide excellent opportunities for improving the electrical and thermal properties of Sb-based materials for engineering various electronic device structures. Published under an exclusive license by the AVS.