Cyclotron Resonance in Metals in a Normal Magnetic Field
No satisfactory theoretical explanation has yet been given for the cyclotron resonance observed in cadmium –, zinc , and potassium , in a magnetic field applied perpendicularly to the metal surface. The resonance peaks in the real part of the surface impedance in potassium have been suggested as being associated with the contribution of the Fermi-liquid cyclotron wave propagating along the magnetic field. The detailed calculation of the surface impedance performed for the spherical Fermi surface in  demonstrates, however, only a very weak singular resonance feature due to the wave in the case of the specular reflection of electrons from the metal surface. The contribution from this wave does not account either for the relatively large peak height or for its shape. A similar disagreement between theoretical predictions and experimental results is found in , where the resonance peak in the derivative of the real part of the surface impedance for cadmium was attributed to the contribution from the vicinities of the limiting points of the electron lens. The theoretical estimate made for the case of the specular reflection of electrons in this study was significantly underestimated, too. The disagreement between theoretical and experimental results can be considerably reduced, if the diffuse reflection of electrons from the metal surface is assumed in the calculation of the impedance. This assumption seems to be unrealistic since it hardly agrees with the anomalous character of the skin effect in all experiments with metals exhibiting cyclotron resonance in normal magnetic fields.
KeywordsFermi Surface Cyclotron Resonance Surface Impedance Cyclotron Frequency Principal Term
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