TY - JOUR
T1 - Ground-State Spin Dynamics in d1 Kagome-Lattice Titanium Fluorides
AU - Jiang, Ningxin
AU - Zhou, Jinfei
AU - Hao, Xue-Li
AU - Li, Jingwei
AU - Zhang, Daliang
AU - Bacsa, John
AU - Choi, Eun Sang
AU - Ramanathan, Arun
AU - Baumbach, Ryan E.
AU - Li, Hong
AU - Bredas, Jean-Luc
AU - Han, Yu
AU - La Pierre, Henry S.
N1 - KAUST Repository Item: Exported on 2022-12-21
Acknowledgements: Studies were supported by the Beckman Foundation as part of a Beckman Young Investigator Award to H.S.L. Single-crystal diffraction experiment was performed at the Georgia Institute of Technology SCXRD facility directed by Dr. John Bacsa and established with funding from the Georgia Institute of Technology. This work was performed in part at the Georgia Tech Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (Grant ECCS-1542174). J.L.B. and H.L. acknowledge the support by the Army Research Office under Grant No. W911NF-17-1-0339; (2) X.L.H. acknowledges the support of China Scholarship Council (No. 201806170254). D.Z. thanks the National Key R&D Project of China (2022YFE0113800) and Thousand Talents Program for Distinguished Young Scholars. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida.
PY - 2022/12/19
Y1 - 2022/12/19
N2 - Many quantum magnetic materials suffer from structural imperfections. The effects of structural disorder on bulk properties are difficult to assess systematically from a chemical perspective due to the complexities of chemical synthesis. The recently reported S = 1/2 kagome lattice antiferromagnet, (CH3NH3)2NaTi3F12, 1-Ti, with highly symmetric kagome layers and disordered interlayer methylammonium cations, shows no magnetic ordering down to 0.1 K. To study the impact of structural disorder in the titanium fluoride kagome compounds, (CH3NH3)2KTi3F12, 2-Ti, was prepared. It presents no detectable structural disorder and only a small degree of distortion of the kagome lattice. The methylammonium disorder model of 1-Ti and order in 2-Ti were confirmed by atomic-resolution transmission electron microscopy. The antiferromagnetic interactions and band structures of both compounds were calculated based on spin-polarized density functional theory and support the magnetic structure analysis. Three spin-glass-like (SGL) transitions were observed in 2-Ti at 0.5, 1.4, and 2.3 K, while a single SGL transition can be observed in 1-Ti at 0.8 K. The absolute values of the Curie–Weiss temperatures of both 1-Ti (−139.5(7) K) and 2-Ti (−83.5(7) K) are larger than the SGL transition temperatures, which is indicative of geometrically frustrated spin glass (GFSG) states. All the SGL transitions are quenched with an applied field >0.1 T, which indicates novel magnetic phases emerge under small applied magnetic fields. The well-defined structure and the lack of structural disorder in 2-Ti suggest that 2-Ti is an ideal model compound for studying GFSG states and the potential transitions between spin liquid and GFSG states.
AB - Many quantum magnetic materials suffer from structural imperfections. The effects of structural disorder on bulk properties are difficult to assess systematically from a chemical perspective due to the complexities of chemical synthesis. The recently reported S = 1/2 kagome lattice antiferromagnet, (CH3NH3)2NaTi3F12, 1-Ti, with highly symmetric kagome layers and disordered interlayer methylammonium cations, shows no magnetic ordering down to 0.1 K. To study the impact of structural disorder in the titanium fluoride kagome compounds, (CH3NH3)2KTi3F12, 2-Ti, was prepared. It presents no detectable structural disorder and only a small degree of distortion of the kagome lattice. The methylammonium disorder model of 1-Ti and order in 2-Ti were confirmed by atomic-resolution transmission electron microscopy. The antiferromagnetic interactions and band structures of both compounds were calculated based on spin-polarized density functional theory and support the magnetic structure analysis. Three spin-glass-like (SGL) transitions were observed in 2-Ti at 0.5, 1.4, and 2.3 K, while a single SGL transition can be observed in 1-Ti at 0.8 K. The absolute values of the Curie–Weiss temperatures of both 1-Ti (−139.5(7) K) and 2-Ti (−83.5(7) K) are larger than the SGL transition temperatures, which is indicative of geometrically frustrated spin glass (GFSG) states. All the SGL transitions are quenched with an applied field >0.1 T, which indicates novel magnetic phases emerge under small applied magnetic fields. The well-defined structure and the lack of structural disorder in 2-Ti suggest that 2-Ti is an ideal model compound for studying GFSG states and the potential transitions between spin liquid and GFSG states.
UR - http://hdl.handle.net/10754/686571
UR - https://pubs.acs.org/doi/abs/10.1021/jacs.2c09633
U2 - 10.1021/jacs.2c09633
DO - 10.1021/jacs.2c09633
M3 - Article
C2 - 36534963
SN - 0002-7863
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
ER -