We carried out temperature-dependent (20 - 550 K) measurements of resonant inelastic X-ray scattering on LaCoO3 to investigate the evolution of its electronic structure across the spin-state crossover. In combination with charge-transfer multiplet calculations, we accurately quantized the renormalized crystal-field excitation energies and spin-state populations. We show that the screening of the on-site Coulomb interaction of 3d electrons is orbital selective and coupled to the spin-state crossover in LaCoO3. The results establish that the gradual spin-state crossover is associated with a relative change of Coulomb energy versus bandwidth, leading to a Mott-type insulator-to-metal transition.
@article{arxiv.1708.04417,
title = {Coulomb correlations intertwined with spin and orbital excitations in LaCoO$_3$},
author = {K. Tomiyasu and J. Okamoto and H. Y. Huang and Z. Y. Chen and E. P. Sinaga and W. B. Wu and Y. Y. Chu and A. Singh and R. -P. Wang and F. M. F. de Groot and A. Chainani and S. Ishihara and C. T. Chen and D. J. Huang},
journal= {arXiv preprint arXiv:1708.04417},
year = {2017}
}