Figure 3. Transport properties as a function of temperature.

Seebeck coefficient (a) resistivity (b) total thermal conductivity (c) and lattice thermal conductivity (d) for p-tellurium. The ab initio calculated Seebeck coefficient⁴⁶ is included as solid curves for comparison in a. Majority of the samples studied here show a degenerate p-type semiconducting behaviour and a dominant phonon scattering by Umklapp process (red curve in d). The black dashed line in d shows the estimated minimal lattice thermal conductivity (κ_L^min) according to the Cahill model. Overlying lines are used to guide the eye and the carrier concentrations for the samples are shown in a unit of cm⁻³ in a.