While the superconductivity and density wave orders have been discovered recently in various layered nickelates, the microscopic origins of those electronic orders remain unresolved despite numerous theoretical proposals. Using polarized Raman spectroscopy, we investigate the temperature-dependent evolution of electronic response in trilayer nickelate La₄Ni₃O₁₀. Raman spectra of La₄Ni₃O₁₀ single crystals exhibit a systematic reduction of the incoherent electron continuum across the spin density wave (SDW) transition. Through the polarization-resolved measurements, we uncover that the SDW coherence develops specifically in the symmetric  and nodal  representations. Analysis based on the Fermi surface band curvatures further suggests a partial removal of a conduction band in the crystal momentum positions with a predominant  orbital character. Our observations thus establish the symmetry channels and the active role of  orbitals involved in the SDW formation, which in turn constitutes an important clue to understanding the pressure-driven superconductivity.

 

Publication: Phys. Rev. Lett. 135, 136505 (2025); 
https://doi.org/10.1103/1tp1-y73g