Daily Overview: Today’s highlight work focuses on deepening the understanding of the electronic structure of hybrid Ruddlesden-Popper nickelates. In [1], based on a bilayer t-J model of the d_{x²-y²} orbital combined with first-principles parameters, the researchers successfully unified the explanation of various experimental调控 behaviors of Tc in La₃Ni₂O₇ using slave-boson mean-field and density matrix renormalization group methods. The model reveals particle-hole asymmetric doping dependence: hole doping suppresses Tc while electron doping enhances Tc, thereby explaining the “half-dome” behavior in oxygen content regulation and the decrease of Tc caused by calcium/strontium substitution. Additionally, the variation of Tc with interlayer antiferromagnetic superexchange J⊥ naturally describes the “right triangle” relationship under pressure and the enhancement effect of compressive strain. Compared to weak-coupling theory and the d_{z²} orbital mechanism, this work provides a more unified framework and predicts that electron doping without introducing disorder (e.g., substituting lanthanum with higher-valent elements) may further increase Tc. arXiv submission processing window: 2026-05-11 00:00 to 2026-05-11 00:00 UTC.

1. A Unified Understanding of the Experimental Controlling of the T$_\text{c}$ of La$_3$Ni$_2$O$_7$

Summary: Based on an effective double-layer t-J∥-J⊥ model with d_{x²-y²} orbitals and input parameters from first-principles calculations, the model solved using slave-boson mean-field and density matrix renormalization group methods exhibits superconducting transition temperature (Tc) control behavior similar to that observed in hole-doped overdoped cuprates. Since the d_{x²-y²} orbital is close to quarter filling, the model shows particle-hole asymmetric doping dependence: hole doping drives the system further into the overdoped regime and suppresses Tc, while electron doping alleviates overdoping and enhances Tc, thereby explaining the Tc reduction upon introducing hole doping via increasing oxygen content or Ca/Sr substitution for La, as well as the “half-dome” behavior under oxygen content tuning. Regarding interaction strength, Tc varies with the interlayer antiferromagnetic superexchange J⊥, which accounts for experimental observations such as the enhancement of bulk Tc by Sm/Nd substitution for La under pressure, the pressure-dependent “right-triangle” shaped Tc-pressure relation, and the increase of Tc under compressive strain in thin films. Compared to weak-coupling theory (where Tc primarily depends on density of states) and pairing mechanisms dominated by the d_{z²} orbital (where Tc is proportional to the d_{z²} hole density), this model provides a more natural and unified explanation. Accordingly, it is suggested that electron doping without introducing disorder (e.g., by substituting La with higher-valent elements) may increase Tc.