Measurements of the Fermi surface of SrTiO3: Nb

The oscillatory magnetothermal effect has been used to study the Fermi surface of niobium-doped strontium titanate at low temperatures. Several de Haas-van Alphen frequencies were identified in the (011) crystallographic plane and compared with the predictions of various theoretical models of the conduction band. The many-ellipsoid model cannot be reconciled with the data. The warped-band model of Mattheiss, which predicts the Fermi surface to consist of two disjoint sheets at the center of the zone, appears to be consistent with most prominent features of the experimental results. The implications of this band structure for superconductivity in SrTi${\mathrm{O}}_3$ remain to be explained.