Magnetic Field-Induced Semimetal-Semiconductor Transition in Bi

Abstract

The unusual behavior of the lowest quantum-number j=0 Landau levels of the electrons in Bi has important consequences for the description of a magnetic field-induced semimetal-semiconductor transition. We discuss a quantitative treatment of the j=0 Landau levels, based upon the Baraff Hamiltonian, and including the k_H-dependence. Magnetoreflection experiments over a range of photon energies on Bi, Bi₉₈Sb₂ and Bi₉₇Sb₃ for $\overrightarrow H$ || binary axis provide experimental confirmation for the model. For large H, the k_H-dependence of the j=0 levels is anomalous, showing a “camel-back” shape. As the j=0 conduction band level at k_H=O crosses E_F, magnetic field-induced carrier pockets are formed away from k_H=0. The implications of these magnetic field-induced pockets on a semimetal-semiconductor transition are discussed.

Work supported by the National Science Foundation