Effect of surface scattering of conduction electrons on the oscillations of the impedance of a thin tungsten plate

The effect of the character of the surface scattering of conduction electrons on the oscillations of the rf impedance of thin tungsten films with n‖[100] (n is the normal to the surface) in a magnetic field H‖n is studied experimentally under the conditions of an ultrahigh vacuum. The multiple Sondheimer effect is used to determine the specularity parameter for resonance carriers. It is established that the amplitude of the oscillations of the real part of the impedance ΔR is proportional to the product of two competing factors (R2 + x2) (1 — pd)2 in the region where doppleron oscillations predominate or (R2 − X2) (1 − pd)2 in the region where the Gantmakher-Kaner oscillations predominate (R and X are the real and imaginary parts, respectively, of the impedance and pd is the specularity parameter for the resonance electrons). This results in a nonmonotonic dependence of ΔR on the probability for specular reflection of electrons by the surface of the sample. The drop in the amplitude of the impedance oscillations as pd increases occurs unambiguously only at the transition to predominately specular reflection of electrons (pd > 0.5) It is also established that the anharmonicity of the doppleron oscillations, characterized by the relative contribution of the second harmonic, depends on the state of the surface and increases as pd increases. The value of pd is calculated based on the ratio of the amplitudes of the first two Fourier components of the doppleron oscillations.