Electron-phonon associated carrier mobility in MgSe and MgTe

Electron-phonon (E-p) coupling incorporated density functional theory (DFT) based investigation of structural, electronic and vibrational properties of bulk MgSe and MgTe is presented. Electron-phonon coupling is incorporated to understand its effect on charge carrier dynamics. It is observed that the MgTe possesses room temperature hole and electron mobility of 18.7 cm2/Vs and 335 cm2/Vs, respectively; in contrast to this, the bulk MgSe follows reverse trend in temperature dependent carrier mobilities owing to its different scattering rate and electron-phonon coupling profiles. The key feature of the study was to showcase the importance of electron-phonon coupling in determining the carrier mobility and the relative dynamics in the material. Further, the incorporation of e-p coupling softens the electronic and phonon dispersions which is subjected to the inclusion of the interaction between the electrons and the phonons of the systems. The overall results indicate that the incorporation of the electron-phonon coupling is crucial in determining the carrier dynamics of the system which is in excellent agreement with the experimental findings. Both materials possess moderate magnitudes of mobilities that are subjected to the modification by means of changing the dimensional confinement and/or chemical composition that can strongly influence the carrier dynamics by means of altered edge states and coupling parameters.

Maitry Joshi, Trupti K Gajaria, Prafulla K. Jha · 2024