Valence, charge transfer, and orbital-dependent correlation in bilayer nickelates Nd3Ni2O7

• DOI: 10.1103/physrevb.111.165101
• Publication Date: 2025-04-02T03:35:17Z
• Authors: Daisuke Takegami; Takaki Okauchi; Edgar Abarca Morales; Koto Fujinuma; Mizuki Furo; Masato Yoshimura; Ku-Ding Tsuei; Grace A. Pan; Dan Ferenc Segedin; Qi Song; Hanjong Paik; Charles M. Brooks; Julia A. Mundy; Takashi Mizokawa; Liu Hao Tjeng; Berit H. Goodge; Atsushi Hariki

We examine the bulk electronic structure of Nd3Ni2O7 using Ni 2p core-level hard x-ray photoemission spectroscopy combined with density functional theory + dynamical mean-field theory. Our results reveal a large deviation of the Ni 3d occupation from the formal Ni2.5+ valency, highlighting the importance of the charge transfer from oxygen ligands. We find that the dominant d8 configuration is accompanied by nearly equal contributions from d7 and d9 states, exhibiting an unusual valence state among Ni-based oxides. Finally, we discuss the Ni dx2−y2 and dz2 orbital-dependent hybridization, correlation and local spin dynamics.

Published by the American Physical Society 2025