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Octa-Kagomé Lattice Compounds Showing Quantum Critical Behaviors: Spin Gap Ground State versus Antiferromagnetic
Yingying Tang1, Cheng Peng2, Wenbin Guo1
1State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People's Republic of China.
Abstract:
Search for a new geometrically frustrated lattice is a great challenge. Herein, we report on a successful synthesis of two new layered compounds BiOCu2(XO3)(SO4)(OH)·H2O [X = Te (1) and Se (2)] with a new type of geometrically frustrated lattice (i.e., the octa-kagomé lattice) between kagomé and star motifs. Magnetic measurements confirmed that 1 exhibits a spin gap ground state, while 2 possesses a typical antiferromagnetic ordering at low-temperature. Such different magnetic behaviors between two isostructural compounds are suggested to originate from a slightly structural modification induced by nonmagnetic XO3 anionic groups. Theoretical simulations suggest that the origin of gapped ground state in 1 may be due to the dimerization of Cu2+ ions, while 2 may break the limiting of such dimerization, leading to an antiferromagnetic ordering.
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