Matter–light interaction is at the center of diverse research fields from quantum optics to condensed matter physics, opening new fields like laser physics. A magnetic exciton is one such rare example found in magnetic insulators. However, it is relatively rare to observe that external variables control matter-light interaction. Here, it is reported that the broken inversion symmetry of multiferroicity can act as an external knob enabling magnetic excitons in the van der Waals antiferromagnet NiI2. It is further discovered that this magnetic exciton arises from a transition between Zhang–Rice-triplet and Zhang–Rice-singlet fundamentally quantum-entangled states. This quantum entanglement produces an ultrasharp optical exciton peak at 1.384 eV with a 5 meV linewidth. The work demonstrates that NiI2 is 2D magnetically ordered with an intrinsically quantum-entangled ground state.
|Publication status||Published - 2022 Mar 10|
Bibliographical noteFunding Information:
S.S., Y.L., Jae Ha Kim, and B.H.K. contributed equally to this work. The authors acknowledge the helpful discussion with Ki‐Hoon Lee. Work at CQM and SNU was supported by the Leading Researcher Program of the National Research Foundation of Korea (Grant No. 2020R1A3B2079375). Work at Yonsei University was supported by National Research Foundation (NRF) grants funded by the Korean government (MSIT; grant 2021R1A2C3004989) and the SRC program (vdWMRC; grant 2017R1A5A1014862). Work at Sogang Univ. was supported by the National Research Foundation (NRF) grant funded by the Korean government (MSIT) (2019R1A2C3006189; 2017R1A5A1014862, SRC program: vdWMRC center). B.H.K. and Y.W.S. at KIAS were supported by KIAS Individual Grants (CG068702), and numerical computations have been performed with the Center for Advanced Computation Linux Cluster System at KIAS. The work at POSTECH and MPK was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (Grant No. 2016K1A4A4A01922028 and No. 2020M3H4A2084417). The work at GIST was supported by the Ministry of Science, ICT, and Future Planning (Nos. 2015R1A5A1009962, 2018R1A2B2005331). The authors acknowledge Diamond Light Source for time on beamline I21.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering