Absorption and phase velocity dispersion of circularly polarised ultrasonics under doppleron-phonon resonance in tungsten

Absorption and phase velocity dispersion of circularly polarised ultrasonics are studied under DPR (doppleron-phonon resonance) conditions in tungsten. It is found experimentally that the magnetic field dependence of ultrasonic absorption on resonant polarisation is represented by an asymmetric peak, sometimes doublet, whereas the dependence of phase velocity is plotted as a distorted dispersion curve. Absorption of another polarised mode exhibits an antiresonant peculiarity (absorption decrease). The deformation potential given by lambda ij =-3v i p j (v and p are the velocity and momentum of electron, respectively) and the Fermi surface model represented by two semispheroids having concavities near the limiting points are used to explain the main features of the phenomenon considered. Determination of the doppleron dispersion relation and of the Hall components of non-local conductivity with the help of DPR data is discussed.