We report the observation of multiple phonon satellite features in ultra thin superlattices of form nSrIrO3/mSrTiO3 using resonant inelastic x-ray scattering. As the values of n and m vary the energy loss spectra show a systematic evolution in the relative intensity of the phonon satellites. Using a closed-form solution for the cross section, we extract the variation in the electron-phonon coupling strength as a function of n and m. Combined with the negligible carrier doping into the SrTiO3 layers, these results indicate that tuning of the electron-phonon coupling can be effectively decoupled from doping. This work showcases both a feasible method to extract the electron-phonon coupling in superlattices and unveils a potential route for tuning this coupling which is often associated with superconductivity in SrTiO3-based systems.
@article{arxiv.1810.08327,
title = {Decoupling carrier concentration and electron-phonon coupling in oxide heterostructures observed with resonant inelastic x-ray scattering},
author = {D. Meyers and Ken Nakatsukasa and Sai Mu and Lin Hao and Junyi Yang and Yue Cao and G. Fabbris and Hu Miao and J. Pelliciari and D. McNally and M. Dantz and E. Paris and E. Karapetrova and Yongseong Choi and D. Haskel and P. Shafer and E. Arenholz and Thorsten Schmitt and Tom Berlijn and S. Johnston and Jian Liu and M. P. M. Dean},
journal= {arXiv preprint arXiv:1810.08327},
year = {2018}
}