Charge order lock-in by electron-phonon coupling in La1.675Eu0.25Sr0.125CuO4

• Published in: Science advances 2021-06, Vol.7 (27)
• Main Authors: Wang, Qisi, von Arx, Karin, Horio, Masafumi, Mukkattukavil, Deepak John, Kuspert, Julia, Sassa, Yasmine, Schmitt, Thorsten, Nag, Abhishek, Pyon, Sunseng, Takayama, Tomohiro, Takagi, Hidenori, Garcia-Fernandez, Mirian, Zhou, Ke-Jin, Chang, Johan
• Format: Article
• Language: English
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.abg7394

Charge order is universal to all hole-doped cuprates. Yet, the driving interactions remain an unsolved problem. Electron-electron interaction is widely believed to be essential, whereas the role of electron-phonon interaction is unclear. We report an ultrahigh-resolution resonant inelastic x-ray scattering (RIXS) study of the in-plane bondstretching phonon mode in stripe-ordered cuprate La1.675Eu0.25Sr0.125CuO4. Phonon softening and lifetime shortening are found around the charge ordering wave vector. In addition to these self-energy effects, the electron-phonon coupling is probed by its proportionality to the RIXS cross section. We find an enhancement of the electron-phonon coupling around the charge-stripe ordering wave vector upon cooling into the low-temperature tetragonal structure phase. These results suggest that, in addition to electronic correlations, electron-phonon coupling contributes substantially to the emergence of long-range charge-stripe order in cuprates.