Thermo-and galvanomagnetic properties of lead chalcogenides at high pressures up to 20 GPa

The Nernst-Ettingshausen (NE) effect in the initial NaCl and high-pressure GeS phases was studied at a high pressure $P$ for $n$-PdTe, $p$-PbSe, and $p$-PbS to estimate the mobility $\mu$ and the charge-carrier scattering parameter $r$. It was found that the transverse and longitudinal NE effects in PbTe and PbSe increase with pressure, indicating the transition to the gapless state near $P\approx3$ GPa. The sign of the transverse NE effect changes because of the change in the electron scattering mechanism in the GeS phase. The experimentally observed weakening of the NE and magnetoresistance effects at high $P$ gives evidence for the indirect energy gap $E_g$ in the high pressure phases with GeS structure.