Studies of the Free and Bound Magneto-Polaron and Associated Transport Experiments in n-InSb and Other Semiconductors

Abstract

Although only of limited technological application InSb is of great interest to semiconductor physicists on account of its small forbidden energy gap (0.2eV) and its metallurgical properties which allow samples to be prepared with background concentrations of inadvertently-introduced electrically-active impurities of the order of 1014 cm-3. The small energy gap gives rise to a very low effective mass at the conduction band edge, large band non-parabolicity and a very large effective g-factor on account of the strong spin-orbit interaction. The small effective mass gives rise to a very high electron mobility which can approach 106 cm2/Vs at liquid nitrogen temperatures and to a very large cyclotron energy\((\hbar {\omega _c}{\text{ where }}{\omega _c} = eB/m*)\), such that this energy becomes equal to that of the longitudinal optical phonons at the relatively modest magnetic field of 3T. As a consequence, even though the Frohlich coupling constant α is quite small on account of the low mass, much of pioneering studies of magneto-polaron and associated effects such as the magnetophonon effect observed in the electrical resistance of semiconductors were performed with this material.(see for example reviews by Harper et al (1) and by Levinson and Rashba (2)).