Nickelate La4Ni3O10-ฮด 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(๐๐๐ฏ๐๐ ) of La4Ni3O10-ฮด is nearly isotropic, with the anisotropic parameter ฮณ 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 ๐ ๐ณ๐ and ๐ ๐ฑ๐−๐ฒ๐ 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 3๐x2−y2 orbitals, which has the precise roles of the ๐z2 and ๐x2−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