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Quantum Correlated Plasmons and Their Tunability in Undoped and Doped Mott-Insulator Cuprates
Version 2 2019-11-18, 14:50
Version 1 2019-10-30, 12:04
journal contribution
posted on 2019-11-18, 14:50 authored by Xinmao Yin, Chi Sin Tang, Shengwei Zeng, Teguh Citra Asmara, Ping Yang, M. Avicenna Naradipa, Paolo E. Trevisanutto, Tomonori Shirakawa, Beom Hyun Kim, Seiji Yunoki, Mark B. H. Breese, Thirumalai Venkatesan, Andrew T. S. Wee, Ariando Ariando, Andrivo RusydiPlasmons, collective excitations of charge density, have
attracted much interest in fundamental science and applications. While
plasmons have been observed in metal-like phase of high-Tc superconductors,
they have not been reported in the Mott-insulating form. Here, we
report a new quantum correlated plasmons in ambipolar Y1–zLaz(Ba1–xLax)2Cu3Oy and optimal-doped YBa2Cu3O7–x using high-resolution
spectroscopic ellipsometry. Interestingly, as functions of hole, electron-doping,
and temperature, their dynamical loss-function and dielectric-functions
exhibit formation of two plasmons at multiple ordered low- and high-photon
energies due to on-site Cu3d Coulomb interaction
and antibonding O2p–Cu3d.
While the low-energy correlated plasmon transforms into a conventional-plasmon
upon doping, the high-energy correlated plasmon remains. The intensity
of these plasmons follows a mixture of singlet and triplet with decreasing
temperature. Besides, their dephasing time decreases with increasing
doping. Our result highlights the importance of charge-spin coupling
in the correlated plasmons, which may potentially reveal a photon–electron
interaction in the localized states of Mott-insulators.