t−J model for strongly correlated two-orbital systems: Application to bilayer nickelate superconductors

Tatsuya Kaneko; Masataka Kakoi; Kazuhiko Kuroki

doi:10.1103/bsgt-sg2s

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t−J model for strongly correlated two-orbital systems: Application to bilayer nickelate superconductors

Tatsuya Kaneko, Masataka Kakoi, Kazuhiko Kuroki

DOI 10.1103/bsgt-sg2s · Physical Review B

T1

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Abstract

We derive a t−J model applicable to strongly correlated two-orbital systems including bilayer nickelate superconductors. Using the Schrieffer-Wolff transformation, we exclude the doubly occupied states, which raise the onsite Coulomb energy, and derive the resulting spin interactions from the two-orbital Hubbard model. We also introduce effective interactions attributed to the interorbital Coulomb interaction. To adapt the effective model to bilayer nickelates that exhibit high-temperature superconductivity, we quantitatively evaluate the strengths of the spin interactions based on the hopping parameters in La3Ni2O7. Considering the evaluated effective interactions, we propose a simplified t−J model for bilayer nickelate superconductors.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
La3Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	80	Pressure not reported	onset
La2PrNi2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	80	Pressure not reported	onset
La4Ni3O10 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown