# Anomalous anisotropic exciton temperature dependence in rutile ${\mathrm{TiO}}_{2}$

• Baldini, Edoardo Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, Switzerland
• Dominguez, Adriel Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany
• Chiodo, Letizia Unit of Nonlinear Physics and Mathematical Modeling, Department of Engineering, Università Campus Bio-Medico di Roma, Italy
19.07.2017
Published in:
• Physical Review B. - 2017, vol. 96, no. 4, p. 041204
English 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 TiO2, revealing a strong anisotropic polarization dependence with increasing temperature, namely, an anomalous blue shift for light polarized along the a axis and a conventional red shift for light polarized along the c 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 a-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.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
• English
Classification
Physics
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/306044