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arXiv · 2505.23502

Dominant Kitaev interaction and field-induced quantum phase transitions in triangular-lattice KCeSe2

Mingtai Xie·Zheng Zhang·Weizhen Zhuo·Wei Xu·Jinfeng Zhu·Jan Embs·Lei Wang·Zikang Li·Huanpeng Bu·Anmin Zhang·Feng Jin·Jianting Ji·Zhongwen Ouyang·Liusuo Wu·Jie Ma·Qingming Zhang
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Abstract

Realizing Kitaev interactions on triangular lattices offers a compelling platform for exploring quantum-spin-liquid physics beyond the conventional honeycomb lattice framework. Here, we investigate the triangular-lattice antiferromagnet KCeSe2, where multiple probes reveal strong magnetic anisotropy suggesting significant Kitaev physics. Through detailed and combined analysis of magnetization, neutron scattering, and thermodynamic experiments, we identify dominant ferromagnetic Kitaev ($K = -1.82$ K) and antiferromagnetic Heisenberg ($J = 1.34$ K) interactions that stabilize a stripe-$yz$ ordered ground state via an order-by-disorder mechanism. Magnetic fields applied along the Kitaev bond direction induce two phase transitions at 1.67 T and 3.8 T, consistent with density matrix renormalization group (DMRG) calculations predictions of a progression from stripe-$yz$ to stripe-canted and spin-polarized phases. Near the 1.67 T quantum critical point, enhanced quantum fluctuations suggest conditions favorable for exotic excitations. These results establish KCeSe2 as a platform for exploring Kitaev physics on triangular lattices.

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Mingtai Xie, Zheng Zhang, Weizhen Zhuo, Wei Xu, Jinfeng Zhu, Jan Embs, Lei Wang, Zikang Li, Huanpeng Bu, Anmin Zhang, Feng Jin, Jianting Ji, Zhongwen Ouyang, Liusuo Wu, Jie Ma, Qingming Zhang. 2025-05-29. Dominant Kitaev interaction and field-induced quantum phase transitions in triangular-lattice KCeSe2. https://doi.org/10.1103/physrevresearch.7.023198

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