Transport measurements on positive-gapHg1−xMnxTewith the use of an alternating-current technique

Abstract

An alternating-current technique was used to measure the resistivity and Hall coefficient of single crystals of positive-gap ${\mathrm{Hg}}_{1-x}{\mathrm{Mn}}_x\mathrm{Te}$ over the temperature range from 2 to 300 K and for magnetic fields up to 26 kG. In a $p$-type ${\mathrm{Hg}}_{0.81}$ ${\mathrm{Mn}}_{0.19}$Te crystal, the resistivity and Hall coefficient were observed to decrease with increasing magnetic field for temperatures below 60 K. At 20 K the Hall coefficient and the resistance had both decreased about a factor of 2 by 26 kG. This behavior was attributed to a change in the binding energy of an acceptor of between -0.15 and -0.19 meV/kG. In a degenerate, $n$-type ${\mathrm{Hg}}_{0.84}$ ${\mathrm{Mn}}_{0.16}$Te crystal we studied Shubnikov—de Haas oscillations whose amplitudes varied nonmonotonically with temperature. This behavior was attributed to the temperature variation of the exchange interaction, from which the exchange integral, $N_0\alpha$, was estimated to be -0.6 eV.