Topological Transitions in the Strain Dependences of Thermopower and Resistance in Nanowires Based on Bi –Sn

Abstract

We studied the strain dependences of the resistance and thermopower of nanowires of Bi and its alloys with Sn in conditions of an anisotropic elastic strain with values of 2% elongation, which is one order of magnitude higher than the value achieved in the bulk samples. Glass-coated wires with diameters ranging from 150 nm to a few microns were prepared by liquid phase casting; they were single crystals with a strictly cylindrical shape. The change in the Fermi surface was calculated using Shubnikov de Haas oscillations. In thin wires of Bi doped with Sn the anomalies in thermopower were found out: the peculiarities on the deformation dependences of the thermopower α(ξ) in Bi-0.025at%Sn of the thermopower. The peculiarities in deformation curves of thermopower connected with electron topological transitions (ETT). The interband scattering plays key role in manifestations of above mentioned anomalies in thermopower at ETT which takes place only in doped Bi-wires at low temperatures. It is shown that the high concentrations and higher temperatures leads to a reduction in the thermopower anomalies which corresponds to the exit from the ETT.