Electron-phonon deformation potential interaction in core-shell Ge-Si and Si-Ge nanowires

TL;DR

This paper derives a comprehensive Hamiltonian for electron-phonon interactions in core-shell Ge-Si and Si-Ge nanowires, analyzing size and strain effects on coupling strengths and vibrational modes to aid in nanosystem characterization.

Contribution

It provides a general analytical expression for the electron-phonon deformation potential Hamiltonian in non-polar core-shell nanowires, including size and strain effects.

Findings

Derived analytical DP Hamiltonian for core-shell nanowires.

Analyzed size dependence and strain-induced shifts in phonon modes.

Reported numerical results for vibrational frequencies and coupling strengths.

Abstract

We settle a general expression for the Hamiltonian of the electron-phonon deformation potential (DP) interaction in the case of non-polar core-shell cylindrical nanowires (NWs). On the basis of long range phenomenological continuum model for the optical modes and by taking into account the bulk phonon dispersions, we study the size dependence and strain-induced shift of the electron-phonon coupling strengths for Ge-Si and Si-Ge NWs. We derive analytically the DP electron-phonon Hamiltonian and report some numerical results for the frequency core modes and vibrational amplitudes. Our approach allows for the unambiguous identification of the strain and confinement effects. We explore the dependence of mode frequencies and hole-DP scattering rates on the structural parameters of these core-shell structures, which constitute a basic tool for the characterization and device applications of these novel nanosystems.