The Zhang-Rice exciton state in ${\mathrm{NiPS}}_3$, closely connected to the underlying zigzag antiferromagnetic order, is a representative case of intricate interaction among quasiparticles in van der Waals magnets. ${\mathrm{NiPS}}_3$ is usually described by a XXZ-type Hamiltonian below its Néel temperature of 155 K. The spin-orbit entangled Zhang-Rice exciton state of ${}^1{A}_{1\mathrm{g}}$ symmetry emerges at 1.4756 eV below $T_{\mathrm{N}}$ and becomes exceptionally prominent below about 50 K where the full width at half maximum reaches 0.4 meV, narrower than the thermal fluctuation $k_{\mathrm{B}}T$. Here, we report a second Zhang-Rice exciton state in ${\mathrm{NiPS}}_3$ observed at 1.0975 eV by conducting temperature-dependent high-resolution transmittance measurements on bulk ${\mathrm{NiPS}}_3$ single crystals over the frequency range 0.62–2 eV. We identify the second Zhang-Rice exciton state to result from the initial Zhang-Rice triplet ground state ${}^3{A}_{2\mathrm{g}}$ to the excited Zhang-Rice singlet state ${}^1{E}_{\mathrm{g}}$. In addition, the ${}^3{T}_{2\mathrm{g}}$ state, which overlapped with the ${}^1{E}_{\mathrm{g}}$ state, split to ${}^3{E}_{\mathrm{g}}$ and ${}^3{A}_{1\mathrm{g}}$ states as the temperature decreased, and the temperature dependence of their parameters changed below $T_{\mathrm{N}}$. Our results offer valuable information on the intricate electronic structure of ${\mathrm{NiPS}}_3$, where charge transfer and spin-orbit entanglement bring in an exciting arena to study many-body interactions.

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• Electronic structure
• Excitons
• Magnetism
• Antiferromagnets
• van der Waals systems