Dielectric Constant of PbTe

The low frequency dielectric constant of PbTe was determined by measuring the barrier capacitances of PbTe abrupt junctions at about 100 kc/s and low temperatures. The junctions were made by alloying In to p-type base crystals or Ag-Te alloy to n-type crystals. The donor or acceptor density in crystals was controlled by heat treatment to range from 1.5×10¹⁷ to 8.0×10¹⁸ cm^-3. As the low frequency dielectric constant of PbTe a value of 400 was obtained, which is approximately constant in the temperature range from 4.2 to 130^°K and in the frequency range from 10 to 150 kc/s. This high value of dielectric constant is sufficient to explain the large value of carrier mobility in PbTe at low temperatures.