Abstract
We report the observation of multiple phonon satellite features in ultrathin superlattices of the form nSrIrO3/mSrTiO3 using resonant inelastic x-ray scattering (RIXS). 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 RIXS 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 the tuning of the electron-phonon coupling can be effectively decoupled from doping. This work both showcases 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.
| Original language | English |
|---|---|
| Article number | 236802 |
| Journal | Physical Review Letters |
| Volume | 121 |
| Issue number | 23 |
| DOIs | |
| State | Published - Dec 7 2018 |
Funding
The authors acknowledge useful discussions with Wei-Guo Yin, Yilin Wang, Lukas Horak, Chris Rouleau, and Neil J. Robinson. The authors also acknowledge helpful correspondence with Simon Moser. The authors also acknowledge experimental assistance from Milan Radović for the use of a substrate. This material is based upon work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Early Career Award Program under Grant No. 1047478. Work at Brookhaven National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-SC0012704. The RIXS experiments were performed at the ADRESS beam line of the Swiss Light Source at the Paul Scherrer Institut. Work at the Paul Scherrer Institut was supported by the Swiss National Science Foundation through the National Competence Center for Research “MATERIALS’ REVOLUTION: COMPUTATIONAL DESIGN AND DISCOVERY OF NOVEL MATERIALS” (MARVEL), the SINERGIA network “Mott Physics Beyond the Heisenberg Model in Iridates and Related Materials” (SNSF Research Grant No. CRSII2_160765/1) and a D-A-CH project (SNSF Research Grant No. 200021L 141325).. J. P. and T. S. acknowledge financial support through the Dysenos AG by Kabelwerke Brugg AG Holding, Fachhochschule Nordwestschweiz, and the Paul Scherrer Institut. J. P. also acknowledges financial support by the Swiss National Science Foundation Early Postdoc Mobility fellowship Project No. P2FRP2_171824. J. L. acknowledges the support by the Science Alliance Joint Directed Research and Development Program and the Organized Research Unit at the University of Tennessee. J. L. also acknowledges support by the DOD-DARPA under Grant No. HR0011-16-1-0005. A portion of the fabrication, characterization, and theoretical calculations by T. B. was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility operated under Contract No. DE-AC02-05CH11231. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. DOE, OS by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under Contract No. DE-AC02-05CH11231.
| Funders | Funder number |
|---|---|
| DOD-DARPA | HR0011-16-1-0005 |
| Dysenos AG | |
| Kabelwerke Brugg AG Holding | |
| National Competence Center for Research | |
| U.S. Department of Energy | DE-AC02-05CH11231, DE-AC02-06CH11357 |
| Office of Science | DE-SC0012704 |
| Basic Energy Sciences | 1047478 |
| Argonne National Laboratory | |
| University of Tennessee | |
| Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung | CRSII2_160765/1, 200021L 141325 |
| Haute école Spécialisée de Suisse Occidentale | P2FRP2_171824 |