The temperature dependence of the thermopower in Bi whiskers of different thickness (0.3 to 6 μm) is measured within the temperature range 77 to 300 K. At low temperatures the thermopower in the thinnest whiskers changes its sign and becomes positive. Theoretical calculations of the thermopower in Bi whiskers are carried out taking into account the phonon drag effect. Numerical computations prove that the change of sign of the thermopower in thin Bi whiskers at low temperature is caused by phonon drag effect.

There is renewed focus on the thermoelectric properties of Bi-Sb. Reduced dimensionality samples of these alloys, such as nanowires, may exhibit exotic behavior that relate to the properties of the surfaces of topological insulators. It has been predicted that surface states of topological insulators have large thermopower and also ultrahigh mobilities. The authors report results of magneto-thermoelectric investigation of single crystal Bi 1-x Sb x nanowires in a glass cover with diameters ranging from 90 nm to 5 μm. The wide-ranging antimony concentration (0.01 < x < 0.2) enabled us to study the effect of nanowire dimensionality the (bulk) semimetal (x <0.05), semi-conductor 0.08

The dependence of the Nernst-Ettingshausen longitudinal effect on the direction of the magnetic field for the case of semimetals is studied theoretically and experimentally. A quite unique correspondence is found between the anisotropy of the effect and the band structure near the Fermi level. It is shown that the commutation effect which determines the dependence of the magneto-thermo-e.m.f. magnitude on the direction of the induction vector, permits to judge about the number and localization of band extrema in the k-space. This is an effective way for studying band structures of bismuth and its alloys a t high temperatures. The results of CE studies in bismuth and its alloys art 100 O K are given below. Theory of Thermomagnetic EffectsThe expression for the electric current density J is given as follows :where oi,(B) is the generalized electroconductivity tensor, E, the electric field, 0, T the temperature gradient.The tensor Pir(B) is determined by the correlation

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