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SM ISO690:2012 NIKOLAEVA, Albina, KONOPKO, Leonid, TSURKAN, Ana, ISTRATII, Evghenii. NNN 20P Thermoelectric properties of Bi wires strongly doping donor impurity. In: Materials Science and Condensed Matter Physics, 13-17 septembrie 2010, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2010, Editia 5, p. 215. |
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Materials Science and Condensed Matter Physics Editia 5, 2010 |
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Conferința "Materials Science and Condensed Matter Physics" Chișinău, Moldova, 13-17 septembrie 2010 | ||||||
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Pag. 215-215 | ||||||
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The anomalous dependence of the thermoelectric power on the wire composition in Bi wire, doped with donor impurity up to 1.5at % was observed. This behavior is typical for the Lifshits electronic topological transitions, obtained in the bulk Bi samples doped with Te [1]. In contrast to studies in [2] we also studied the ShdH oscillations on R(H) Bi wires, doped with different degrees of Se and Te to 1.4 at.% Te. Single-crystal wires doped donor impurity Bi were obtained by casting from the liquid phase by the method Ulitovsky in a glass cover [3] with diameters from 300 nm to 5 microns. The position chem. potential of L-electrons was estimated from the Shubnikov de Haas oscillations, which were clearly visible both in longitudinal (H || I), and in the transverse (H ^ I) configuration for Bi-doped wires of all diameters investigated. A clear reduction of the period D(1/H) in the ShdH oscillations from L electronic ellipsoids testifies to displacement of chemical potential deep into L conductivity band at doping. Temperature dependence of thermoelectric power a (T) for Bi wires, doped with donor impurity Te with different positions chem. potential are shown in Fig. 1figureFig. 1 Temperature dependencies of thermopower α(T) in Bi-Te wires: 1. Bi-0.04at.%Te, d=3 μm; 2. Bi0.08at.%Te, d=2,5 μm; 3. Bi-0.1at.%Te, d=2 μm; 4. Bi-0.2at.%Te, d=3 μm; 5. Bi-0.3at.%Te, d=2 μm; 6. Bi0.5at.%Te, d=2 μm; 7. Bi-1.4at.%Te, d=3 μm.Anomalies in thermopower on a(T) Bi wires alloyed consists that dependence a(T) shows essential nonmonotony from structure of an alloying impurity. At doping, thermopower decreases on absolute size practically to «0» at wires Bi-0.3 ат % - 0.5 ат % Te, and at doping to 1,5 ат % Te, thermopower a at Т = 300 К increased again and constitute -70 μV/K (Fig. 1). In Bi wires doping donor impurity Sе was shown a similar anomaly on a(T). Us for the first time have been found out ShdH oscillations from T - band conductivity confirming experimentally occurrence T - band conductivity at doping bismuth by phonon impurity. The effect of the anomalous dependence a(Nd) is interpreted in terms of interband scattering of Lelectrons in the T- conduction band, with a high density of the state, arising at strong doping. |
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