Abstract
Using oxygen -edge x-ray-absorption spectroscopy we show that the holes compensating the impurity charge in are located primarily in the O states rather than in the conventionally assumed Ni states. These holes are bound to the impurities forming states in the NiO band gap. We also argue that these O holes have a very large antiferromagnetic exchange interaction with neighboring () spins, which makes them appear like low-spin states in macroscopic magnetic measurements. This is similar to what could be happening in the Cu-based high- superconductors.
- Received 3 October 1988
DOI:https://doi.org/10.1103/PhysRevLett.62.221
©1989 American Physical Society