• DOI:10.1103/PhysRevB.90.115419
• Corpus ID: 118668450

Acoustic phonons and strain in core/shell nanowires

@article{Kloeffel2014AcousticPA,
  title={Acoustic phonons and strain in core/shell nanowires},
  author={Christoph Kloeffel and Mircea Trif and Daniel Loss},
  journal={Physical Review B},
  year={2014},
  volume={90},
  pages={115419}
}

• C. Kloeffel, M. Trif, D. Loss
• Published 19 May 2014
• Physics
• Physical Review B

We study theoretically the low-energy phonons and the static strain in cylindrical core/shell nanowires (NWs). Assuming pseudomorphic growth, isotropic media, and a force-free wire surface, we derive algebraic expressions for the dispersion relations, the displacement fields, and the stress and strain components from linear elasticity theory. Our results apply to NWs with arbitrary radii and arbitrary elastic constants for both core and shell. The expressions for the static strain are consistent with experiments, simulations, and previous analytical investigations; those for phonons are consistent with known results for homogeneous NWs. Among other things, we show that the dispersion relations of the torsional, longitudinal, and flexural modes change differently with the relative shell thickness, and we identify new terms in the corresponding strain tensors that are absent for uncapped NWs. We illustrate our results via the example of Ge/Si core/shell NWs and demonstrate that shell-induced strain has large effects on the hole spectrum of these systems.