201. Unveiling phase diagram of the lightly doped high-T c cuprate superconductors with disorder removed.
- Author
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Kurokawa K, Isono S, Kohama Y, Kunisada S, Sakai S, Sekine R, Okubo M, Watson MD, Kim TK, Cacho C, Shin S, Tohyama T, Tokiwa K, and Kondo T
- Subjects
- Electronics, Phase Transition, Superconductivity, Copper
- Abstract
The currently established electronic phase diagram of cuprates is based on a study of single- and double-layered compounds. These CuO
2 planes, however, are directly contacted with dopant layers, thus inevitably disordered with an inhomogeneous electronic state. Here, we solve this issue by investigating a 6-layered Ba2 Ca5 Cu6 O12 (F,O)2 with inner CuO2 layers, which are clean with the extremely low disorder, by angle-resolved photoemission spectroscopy (ARPES) and quantum oscillation measurements. We find a tiny Fermi pocket with a doping level less than 1% to exhibit well-defined quasiparticle peaks which surprisingly lack the polaronic feature. This provides the first evidence that the slightest amount of carriers is enough to turn a Mott insulating state into a metallic state with long-lived quasiparticles. By tuning hole carriers, we also find an unexpected phase transition from the superconducting to metallic states at 4%. Our results are distinct from the nodal liquid state with polaronic features proposed as an anomaly of the heavily underdoped cuprates., (© 2023. The Author(s).)- Published
- 2023
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