Anisotropic g‐Factor of the Conduction Electrons in Bi2Te3

Abstract

AbstractShubnikov‐de Haas investigations were performed on n‐type Bi2Te3 in the concentration range from 2 × 1017 up to 2 × 1019 cm−3, at temperatures between 1.6 and 4.2 K. Magnetic fields up to 15 T induction were supplied by a superconducting coil (10 T) and a Bitter‐type magnet (15 T). In contrast to a commonly almost isotropic ratio of spin‐splitting to cyclotron‐splitting in semiconductors, this property shows an anisotropy ratio of more than 20 in n‐Bi2Te3. With knowledge of the electronic mass parameters of the lowest conduction band the angular variation and energy dependence of the corresponding g‐factors were obtained, where the magnitude and sign (g > 0) can he determined. The orbital part of the g‐factor is considerably large along two of the principal axes of the Fermi surface ellipsoids, but completely vanishes along the third principal axis. Hence the g‐factor essen‐rially describes an elliptic disc, the longest principal axis (g′2) tilted by an angle ϑ0 = 33.5° relative to the bisectrix axis within the mirror plane, while the second principal axis (g′1) is parallel to the binary axis. Perpendicular to this plane g′3 ≈ 2 is about an order of magnitude smaller. Values of gmc/(2mo) ≷ 1 may only be explained in a model of more than two interacting energy bands, where additional valence and conduction bands have to be tegarded.