Anisotropic phonon coupling in the magnetophonon resonance in p type tellurium

The magnetophonon effect in p-tellurium is extensively studied over the temperature range from 20 to 90K in magnetic fields of up to 300 kOe. High resolution of the peaks is achieved by means of a double differentiation technique. When the magnetic field is applied perpendicular to the c axis, the position of the magnetophonon peaks in the transverse magnetoresistance differs according to whether the current direction (J) is parallel or perpendicular to the c axis. When the magnetic field is applied parallel to the c axis, the oscillations in the longitudinal magnetoresistance are almost the same order of magnitude as those observed in the transverse magnetoresistance. This rather large amplitude in the longitudinal magnetoresistance is ascribed to the double minimum structure of the energy of the Landau levels.