Anisotropy affects the lattice waves and phonon distributions in GaAs

The stress-strain relationship, anisotropy, heavy- and light-hole structures, and the Phillips ionicity in GaAs are theoretically investigated by Bond matrices model as well as Zener and Every anisotropies. The results show that there is a simple correspondence between anisotropy and the extreme directions of these physical properties, i.e., [0 0 1], [1 1 0] and [1 1 1] directions. Meanwhile the lattice wave propagation, phonon focusing, and phonon distributions in GaAs are also theoretically studied in detail based on lattice-dynamical method. The slowness surface of three lattice waves are the mixing of longitudinal and transverse modes. The feature is that the lattice waves, saddle Gaussian curvatures, and caustic structures are modulated by the anisotropy. The topology in phonon distribution is discussed by the presence of caustics in the anisotropic flux of phonons emanating from a localized phonon distribution. Their topological structures show the phonon distribution and the phonon focusing. The anisotropy not only affects lattice wave propagation and phonon distribution, but influences the phonon focusing. Graphical abstract