MSc Thesis Defence - The Effects of the Electron-Phonon Interaction on the Optical Conductivity of Tilted Dirac Cones

MSc Candidate

Nicholas Gleeson

Abstract

We investigate the effects of the electron-phonon interaction (EPI) on the electronic properties of two-dimensional materials that host an under-tilted Dirac cone as the low-energy electron dispersion. In particular, we examine the signatures produced by the EPI on the electron density of states and energy dispersion, and focus particular attention on the optical conductivity. The optical conductivity depends strongly on tunable parameters, such as chemical potential and the cone tilt, and the signatures of the EPI display richer behaviour than in untilted cones. The effects of the EPI are enhanced as the tilt increases, resulting in stronger renormalization of absorption features, and the visibility of these absorption features depends on the chemical potential and the tilt parameter. Further, the differences in components of the optical conductivity parallel and perpendicular to the tilt direction carry distinct signatures of the EPI that may be used to identify materials hosting under-tilted conical dispersions in experiments.

Examination Committee

• Dr. Robert Wickham, Chair
• Dr. Elisabeth Nicol, Advisor
• Dr. De-Tong Jiang, Advisory Committee
• Dr. Michael Massa, Advisory Committee