Spin Selective Evolution of Zhang-Rice State in Binary Transition Metal Oxide

Abstract

The Zhang-Rice (ZR) state is a strongly hybridized bound state formed by the transition metal and oxygen atoms. The spin-fluctuations within the ZR state are known to play an important role in high-$T_\mathrm{c}$ superconductivity in cuprates. Here, we employ a combination of angle-resolved photoemission spectroscopy (ARPES), X-ray photoemission spectroscopy (XPS), and {\it ab initio} embedded dynamical mean-field theory (eDMFT) to investigate the influence of magnetic ordering on the spectral characteristics of the valence band and Mn 2$p$ core-level in MnO (001) ultrathin films. Our results demonstrate that a complex spin-selective evolution of Mn 3$d$$-$O 2$p$ hybridization develops due to the long-range antiferromagnetic (AFM) ordering. This hybridization significantly alters the spectral shape and weight of the ZR state. Specifically, in the AFM phase, we observed the sharpening of the ZR state and band folding with the periodicity of the AFM unit cell of MnO(001). We also demonstrated a strong connection between the spectral evolution of the ZR state and the non-local screening channels of the photoexcited core holes. Further, our detailed temperature-dependent study reveals the presence of short-range antiferromagnetic correlations that exist at much higher temperatures than $T_\mathrm{N}$. Such comprehensive studies showing the evolution of the ZR state across the magnetic transitions and its implication to the core-hole screening have never been reported in any 3$d$ binary transition metal oxides.