Dynamic Jahn–Teller effect on superconducting excitations in Raman spectra of cuprates

• Dynamic Jahn-Teller effect is studied on the excitations in Raman spectra in cuprates.
• The dynamic electron-phonon coupling shifts the Jahn-Teller excitation peak towards lower energies.
• The Jahn-Teller excitation peak also affected by both the superconducting and the static Jahn-Teller couplings and it shifts towards the lower energies with their increase.

We report a model study of the phonon response due to the interplay of the superconducting (SC) gap, both static and dynamic Jahn–Teller (DJT) distortions and predict the appearance of the Jahn–Teller (JT) distorted SC excitation peaks in the Raman spectra of high-Tc superconductors. The static JT and s-wave type SC interactions in the conduction band are introduced in this model. The phonons are coupled to the conduction electron density as well as to the JT split conduction bands giving rise to DJT interaction, which is the main objective of this communication. The phonons are considered in a harmonic approximation. The phonon Green׳s function and hence the phonon self-energy arising due to normal electron–phonon (EP) interaction and DJT interaction are calculated using Zubarev׳s technique. The phonon self-energy is calculated from the electron response function in the coexistence phase of the two order parameters. Two excitation peaks due to the SC gap and the JT distortion are predicted by phonon density. The evolution of these excitation peaks is investigated by varying different model parameters of the system.