Magnetoreflectivity study of electron-LO phonon interaction in Pb1-xEuxTe and PbTe/Pb1-xEuxTe MultiQuantum Wells

Molecular beam epitaxy(MBE) grown n-type Pb_1-xEu_xTe epilayers and PbTe/Pb_1-xEu_xTe multi-quantum well (MQW) samples were studied at 4 K by magnetoreflectivity in Faraday configuration (B//[111]) in magnetic fields up to 6 Tesla. A strong electron-LO phonon interaction due to the large Froehlich coupling constants is observed in the cyclotron masses for the Pb_1-xEu_xTe epilayers. The cyclotron masses of quasi two dimensional (2D) carriers in PbTe wells (n= 1.5 - 3x10¹¹ cm^-2) of PbTe/Pb_1-xEu_xTe MQW samples do not exhibit a significant resonant electron-polar phonon interaction.