2021年6月16日（水） 17:00~ 理学館506
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Charge order is universal to all hole-doped cuprates. Yet, the driving interactions remain an unsolved problem. Electron-electron interaction is widely believed essential whereas the role of electron-phonon interaction is unclear. In this talk, we report an ultra high resolution resonant inelastic x-ray scattering (RIXS) study of the in-plane bond-stretching phonon mode in stripe-ordered cuprate La_1.675 Eu_0.2 Sr_0.125 CuO₄ . 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 significantly to the emergence of long-range charge-stripe order in cuprates [1,2].

本コロキウムは、第22回QLCセミナーを兼ねています：QLCページ