Phys.org August 1, 2024
An international team of researchers (USA – MIT, Arizona State University, Brookhaven National Laboratory, France, the Netherlands) studied the impact of charge transfer and magnetic order on the excitation spectrum of the nickel dihalides. They detected sharp excitations, analogous to the recently reported excitons and demonstrated that the excitons were dispersive using momentum-resolved resonant inelastic X-ray scattering. The data showed a ligand-mediated multiplet dispersion, which was tuned by the charge-transfer gap and independent of the presence of long-range magnetic order. According to the researchers this reveals the mechanisms governing nonlocal interactions of on-site intra-atomic transitions between d electrons of even parity with the surrounding crystal or magnetic structure, in analogy to ground-state super exchange. The measurements thus established the roles of magnetic order, self-doped ligand holes, and intersite-coupling mechanisms for the properties of dd excitations in charge-transfer insulators… read more. Open Access TECHNICAL ARTICLE
The layered rhombohedral dihalide compounds… Credit: Phys. Rev. X 14, 031007, 12 July 2024