Revisiting the Valence-Band and Core-Level Photoemission Spectra of NiO

Abstract

We have reexamined the valence-band (VB) and core-level electronic structure of NiO by means of hard and soft x-ray photoemission spectroscopies. The spectral weight of the lowest energy state was found to be enhanced in the bulk sensitive Ni 2p core-level spectrum. A configuration-interaction model including a bound state screening has shown agreement with the core-level spectrum and off- and on-resonance VB spectra. These results identify the lowest energy states in the core-level and VB spectra as the Zhang-Rice (ZR) doublet bound states, consistent with the spin-fermion model and recent ab initio calculations within dynamical mean-field theory. The results indicate that the ZR character first ionization (the lowest hole-addition) states are responsible for transport properties in NiO and doped NiO.

Physical characteristics and cation distribution of NiFe2O4 thin films with high resistivity prepared by reactive co-sputtering

“…6 (upper panel)) shows the Ni 2p 3/2 (854.2 eV) and Ni 2p 1/2 (871.6 eV) main peaks followed by a rich satellite structure due to corresponding charge transfer excitations. Except an intense peak at the low binding energy side of NiO 39 (marked by an arrow), which can be attributed to an intrinsic feature found for NiO 40,41 , the Ni 2p spectra of NFO and NiO are very similar to each other, which is consistent for Ni 2+ ions in a high spin state. The lower panel of FIG.…”

High photon energy spectroscopy of NiO: Experiment and theory

“…The electronic structure of NiO has remained enigmatic and controversial over the decades and have also become a major topic of textbooks on condensed matter physics [3][4][5]18,19]. Over the years, a number of x-ray photoemission spectroscopy (XPS) and bremsstrahlung isochromat spectroscopy (BIS) studies [13,[20][21][22][23] were carried out to address its electronic structure. There also have been several theoretical attempts, ranging from model approaches [3,[24][25][26][27]] to first-principles calculations [14,[28][29][30][31][32][33][34][35][36][37], to explain different spectroscopic manifestations of NiO.…”

dd excitations in three-dimensional q-space: A nonresonant inelastic X-ray scattering study on NiO

“…Investigation of their electronic structure, for examples the so-called Zhang-Rice singlet in the cuprates and its relationship with the Hubbard bands across the Mott gap, has been one of the major topics of the field [1][2][3][4][5][6][7][8][9]. Understandably, the atomic scale local dd excitations within the Mott gap has recently raised considerable interests [10][11][12][13][14][15][16][17][18][19], as they provide the building block for the low-energy electronic structure of the crystal.…”