The highest superconducting critical temperatures (Tc) under ambient conditions are found in the trilayer cuprates, drawing widespread attention from both technological and fundamental viewpoints. In this study [1], we use time- and angle-resolved photoemission spectroscopy (tr-ARPES) to examine the low-energy electronic structure and the intertwined orders of Bi₂Sr₂Ca₂Cu₂O_10+d (Bi2223). We reveal a remarkable difference in the dynamic spectral weight response on the underdoped (p = 0.08) and overdoped (p = 0.25) Fermi surfaces, arising from the inner and outer layers of the trilayer, respectively. The momentum and energy dependencies of these dynamics are consistent with a short-range, fluctuating charge order (Q ~ 0.33 r.l.u.) on the inner CuO₂ plane. We validate the presence of this charge order by resonant x-ray scattering on the same samples, firmly establishing the inner plane as underdoped. A systematic comparison of the coherent spectral weight and superconducting gap of single-, bi- and trilayer cuprates of similar doping, supported by complementary single- and three-layer Hubbard model calculations, reveal a unique interlayer mechanism in which both pairing strength and phase coherence are optimized when interfacing planes with distinct hole concentrations [2], providing new microscopic insight into the record T_C of Bi2223.

[1] S.Smit, M.Bluschke et al, arXiv:2506.01448 (2025)

[2] Kivelson, S. A. (2002). Physica B, 318 (1), 61–67.