Abstract
Elucidating the details of electron-phonon coupling in semiconductors and insulators is a topic of pivotal interest, as it governs the transport mechanisms and is responsible for various phenomena such as spectral-weight transfers to phonon sidebands and self-trapping. Here, we investigate the influence of the electron-phonon interaction on the excitonic peaks of rutile , revealing a strong anisotropic polarization dependence with increasing temperature, namely, an anomalous blue shift for light polarized along the axis and a conventional red shift for light polarized along the axis. By employing many-body perturbation theory, we identify two terms in the electron-phonon interaction Hamiltonian that contribute to the anomalous blue shift of the -axis exciton. Our approach paves the way to a complete ab initio treatment of the electron-phonon interaction and of its influence on the optical spectra of polar materials.
- Received 3 April 2017
DOI:https://doi.org/10.1103/PhysRevB.96.041204
©2017 American Physical Society