Publication details
Orbital order and superconductivity in bilayer nickelate compounds
| Authors | |
|---|---|
| Year of publication | 2026 |
| Type | Peer-reviewed scientific article |
| Magazine / Source | PHYSICAL REVIEW B |
| MU Faculty or unit | |
| Citation | |
| web | https://journals.aps.org/prb/abstract/10.1103/4qsd-ws9c |
| Doi | https://doi.org/10.1103/4qsd-ws9c |
| Keywords | Exchange interaction; Spin dynamics; Spin fluctuations; High-temperature superconductors; Strongly correlated systems |
| Attached files | |
| Description | We propose a theory for bilayer nickelate materials, where a large tetragonal field-intrinsic or induced by epitaxial strain-lifts the orbital degeneracy and localizes the 3z2-r2 orbital states. These states host local spins S = 1/2 bound into singlets by strong interlayer coupling, and their dynamics is described by weakly dispersive singlet-triplet excitations ("triplons"). The charge carriers occupy the wide bands of x2-y2 symmetry, and their Cooper pairing is mediated by the high-energy triplon excitations. As the x2-y2 band filling increases, i.e., moving further away from the Ni3+ valence state, the indirect Ruderman-Kittel-Kasuya-Yosida interactions between local spins induce spin-density-wave order via triplon condensation. Implications of the model for compressively strained La3Ni2O7 films and electron-doped oxychloride Sr3Ni2O5Cl2 are discussed. |
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