Cyclotron resonance of both magnetopolaron branches for polar and neutral optical phonon coupling in the layer compound InSe

Abstract

Resonant polaron coupling has been observed by cyclotron resonance of two-dimensional electrons in the polar semiconductor InSe. Both upper and lower branches of the magnetopolaron are seen over a wide range of field (B=18--34 T), allowing an accurate test of polaron theories. A homopolar phonon is also observed to give resonant coupling, via a deformation potential, and we present a theoretical treatment of this coupling mechanism. This gives an accurate value of ${\mathit{g}}^{2}$=0.001\ifmmode\pm\else\textpm\fi{}0.0005 for the coupling constant.