Effect of copper doping on kinetic phenomena in n-Bi2Te2.85Se0.15

Abstract

In single crystals of copper-doped and undoped Bi2Te2.85Se0.15 solid solutions with an electron concentration close to 1 × 1019 cm−3, the temperature dependences are investigated for the Hall (R 123, R 321) and Seebeck (S 11) kinetic coefficients, the electrical-conductivity (σ 11), Nernst-Ettingshausen (Q 123), and thermalconductivity (k 11) coefficients in the temperature range of 77–400 K. The absence of noticeable anomalies in the temperature dependences of the kinetic coefficients makes it possible to use the one-band model when analyzing the experimental results. Within the framework of the one-band model, the effective mass of density of states (m d ≈ 0.8m 0), the energy gap (eg ≈ 0.2 eV), and the effective scattering parameter (r eff ≈ 0.2) are estimated. The obtained value of the parameter r eff is indicative of the mixed electron-scattering mechanism with the dominant scattering by acoustic phonons. Data on the thermal conductivity and the lattice resistivity obtained by subtracting the electron contribution according to the Wiedemann-Franz law are presented.