Far infrared reflectivity spectra of lead-telluride doped with Mn and Yb

PbTe single crystal samples doped with Mn and Yb were grown using the Bridgman method. Far infrared reflectivity spectra were measured at room temperature for samples with different impurity concentrations (total impurity concentration Mn+Yb varied between 0.59 and 2.52 at%, while the impurity Mn/Yb ratio varied between 0 and 3.48). All samples were of the "p" type. Plasma minimum was registered for all samples and varied between 114 and 198 cm(-1) depending on the total impurity concentration and ratio. Samples with lower plasma minimum had a higher free hole mobility, with the highest value of 7000 cm(2)/Vs determined for a sample with the highest Mn/Yb ratio of 3.48 (1.67 at.% Mn and 0.48 at.% Yb)