Galvanomagnetic Effects in p-Type Tellurium at Low Temperatures. II –Transverse and Longitudinal Magnetoresistances of Undoped Crystals–

Abstract

Transverse and longitudinal magnetoresistances of p -type tellurium were investigated in the temperature range from 0.4 K to 4.2 K under magnetic field up to 18 kOe. The samples were not intentionally doped and their carrier concentrations were ranging form 1.9 to 6.6×10 14 cm -3 . The transverse magnetoresistances almost linearly depended on the magnetic field from 1.5 kOe to 18 kOe in contrast to the usual transverse magnetoresistance and they reached a large value of about 500% at 18 kOe around 0.4 K. The longitudinal magnetoresistances also showed linear magnetic field dependences and increased with decreasing temperature. They reached also a large value of about 400% at 18 kOe at 0.4 K. These could be interpreted consistently on the basis of the new kind of two-carrier model in which the impurity band-like states exist at 4.5 K(∼0.4 meV) below the top of the valence band and they shift upward relative to the top of the valence band in the magnetic field. The coefficient of the relative shift is estim...