This literature map synthesizes current research on pressure and strain effects on superconducting pairing in the reduced bilayer nickelate La3Ni2O6. Focusing on the Orbital-Space Bilayer Model (OSBM) framework, it contrasts the proposed s±-wave mechanism in La3Ni2O6 with the Real-Space Bilayer Model (RSBM) applicable to La3Ni2O7. The report analyzes how orbital level offsets and pressure-strain interplay modify electronic structure, compiling evidence from DFT, FLEX, and DMFT studies while identifying experimental gaps regarding superconductivity verification.
Key findings
La3Ni2O6 may exhibit s±-wave superconductivity via the OSBM mechanism driven by interorbital interactions in an incipient-band regime, distinct from La3Ni2O7's RSBM mechanism.
The large orbital level offset (∆E) between Ni d_x2-y2 and other d orbitals, arising from square planar structure without apical oxygens, creates favorable conditions for OSBM superconductivity.
Hydrostatic pressure and biaxial compressive strain suppress octahedral tilts but differ in their effects on the dz2 bonding band position relative to the Fermi level.
While La3Ni2O6 shows metallic behavior above 6.1 GPa, experimental verification of superconductivity remains pending.
Limitations & open questions
Superconductivity in La3Ni2O6 has not yet been experimentally observed, limiting validation of the OSBM predictions.
The analysis relies on theoretical models (DFT, FLEX, cRPA) that may not fully capture strong correlation effects in nickelates.