Trigonal warping of the Fermi surface in n-Bi2Se3

Shubnikov-de Haas investigations on n-type Bi₂Se₃ single crystals were performed in magnetic fields up to 10.5 Tesla (105 kG). The shape of the single-valley Fermi surfaces is almost an ellipsoid of revolution around the trigonal k_c-axis, the longest main axis of the Fermi surface. There is a small amount of flattening in the direction of the k_c-axis and of trigonal warping around the k_c-axis, caused by higher order terms than k²] in the ?(k) relation.