Bilayer Two-Orbital Model of L a 3 N i 2 O 7 under Pressure

The newly discovered Ruddlesden-Popper bilayer ${\mathrm{La}}_{3}{\text{Ni}}_{2}{\mathrm{O}}_{7}$ reaches a remarkable superconducting transition temperature ${T}_{c}\ensuremath{\approx}80\text{ }\text{ }\mathrm{K}$ under a pressure of above 14 GPa. Here we propose a minimal bilayer two-orbital model of the high-pressure phase of ${\mathrm{La}}_{3}{\text{Ni}}_{2}{\mathrm{O}}_{7}$. Our model is constructed with the Ni-$3{d}_{{x}^{2}\ensuremath{-}{y}^{2}}$, $3{d}_{3{z}^{2}\ensuremath{-}{r}^{2}}$ orbitals by using Wannier downfolding of the density functional theory calculations, which captures the key ingredients of the material, such as band structure and Fermi surface topology. There are two electron pockets,…

• NN
  National Natural Science Foundation of China

  Awards: 11974432, 12274472, 92165204, 12174454
• LT
  Leading Talents Program of Guangdong Province

  Award: 201626003
• NK
  National Key Research and Development Program of China

  Awards: 2018YFA0306001, 2022YFA1402802
• BA
  Basic and Applied Basic Research Foundation of Guangdong Province

  Awards: 2022A1515011618, 2021B1515120015