Study of Isotropic superconductivity of Nickelate La4Ni3O10

Nickelate La4Ni3O10-δ was studied here at pressure 50.2 GPa and a magnetic field up to 34T for both out-of-plane (H⊥ab) and in-plane (H//ab) direction.

The upper critical magnetic field(𝝁𝟎𝑯𝐜𝟐 ) of La4Ni3O10-δ is nearly isotropic, with the anisotropic parameter γ monotonically decrease from 1.4 near Tc to 1 at lower temperatures.

By analyzing the upper critical magnetic field using the two-band model, researchers found that the anisotropic diffusivity of the bands, primarily originated from 𝒅𝐳𝟐 and 𝒅𝐱𝟐−𝐲𝟐 orbitals resulting in an unusually isotropic superconducting state.

Interlayer coupling between Ni 3dz2 orbitals and apical oxygen p orbitals at high pressures leads to partially occupied 3𝑑x2−y2 orbitals, which has the precise roles of the 𝑑z2 and 𝑑x2−y2 orbitals in the electron pairing mechanism.

As the field strength increases, superconductivity is gradually suppressed, and the transition shifts to a lower temperature.

https://arxiv.org/pdf/2502.14410