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arXiv · 1712.04906

Excitonic dispersion of the intermediate-spin state in LaCoO$_3$ revealed by resonant inelastic X-ray scattering

Ru-Pan Wang·Atsushi Hariki·Andrii Sotnikov·Federica Frati·Jun Okamoto·Hsiao-Yu Huang·Amol Singh·Di-Jing Huang·Keisuke Tomiyasu·Chao-Hung Du·Jan Kuneš·Frank M. F. de Groot
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Abstract

More than 50 years ago the electron-hole attraction was proposed to drive narrow gap semiconductors or semimetals to a new phase, the excitonic insulator. The experimental proof of its existence in bulk materials remains elusive. In strongly correlated insulators, the proximity of the excitonic insulator phase is reflected by the presence of dispersive electron-hole excitations with a small gap above a singlet ground state. Recently, such an excitation spectrum was proposed to be realized in perovskite oxide LaCoO$_3$. In this Letter we use Co $L_3$-edge resonant inelastic X-ray scattering to put this proposal to experimental test.

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Ru-Pan Wang, Atsushi Hariki, Andrii Sotnikov, Federica Frati, Jun Okamoto, Hsiao-Yu Huang, Amol Singh, Di-Jing Huang, Keisuke Tomiyasu, Chao-Hung Du, Jan Kuneš, Frank M. F. de Groot. 2018-08-07. Excitonic dispersion of the intermediate-spin state in LaCoO$_3$ revealed by resonant inelastic X-ray scattering. https://doi.org/10.1103/physrevb.98.035149

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