Bandgaps properties of â ¢-phosphides (BP, AlP, GaP, InP) materials excited by ultrasonic

First bandgaps of Ⅲ-Phosphides (BP, AlP, GaP, InP) materials excited by ultrasonic is studied in the present paper, in which ultrasonic and terahertz wave collinear transmission is postulated. Numerical simulation results show that, frequencies range of lower polariton branches in polariton dispersion curves are determined by the transverse optical(TO)-phonon frequencies, phonon frequencies are determined by first-principles calculations. Under the acousto-optic interaction, band gaps of polariton dispersion curves are turned on, this leads to a dis-propagation of TO-phonon polariton in Ⅲ-Phosphides bulk. First bandgaps width and acousto-optic coupling strength are proportional with ultrasonic frequency and its intensity. With the increase of ultrasonic frequency, frequencies of bandgaps are blue-shifted, the bandgaps converge to the restrahlen band infinitely with frequency of ultrasonic exceeding over effective value. As is show above, relevant technology may be available in tunable THz frequency selection and filtering.