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arXiv · 2603.03703

NMR evidence of spin supersolid and Pomeranchuk effect behaviors in the triangular-lattice antiferromagnet Rb$_2$Ni$_2$(SeO$_3$)$_3$

Ying Chen·Zhanlong Wu·Xuejuan Gui·Guijing Duan·Shuo Li·Xiaoyu Xu·Kefan Du·Xinyu Shi·Rui Bian·Xiaohui Bo·Guochen Liu·Jun Luo·Jie Yang·Yi Cui·Rui Zhou·Jinchen Wang·Rong Yu·Weiqiang Yu
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Abstract

We performed $^{85}$Rb nuclear magnetic resonance (NMR) measurements on the $S$ = 1 bilayer triangular-lattice antiferromagnet Rb$_2$Ni$_2$(SeO$_3$)$_3$ in magnetic fields up to 26 T. In the field range from 3 T to 26 T, the NMR spectral lines split and their respective spectral weight ratios reveal the existence of the magnetic up-up-down (UUD) phase, although the 1/3-plateau phase is only reached at fields above 16 T. Two distinct gapless regimes are further identified: one at low fields and low temperatures, and the other at high fields and high temperatures, consistent with the spin supersolid Y and V phases. Notably, the UUD-V phase boundary exhibits a negative slope in $dT/dH$, where the supersolid phase is located at temperatures above the solid phase due to strong low-energy spin fluctuations.

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Ying Chen, Zhanlong Wu, Xuejuan Gui, Guijing Duan, Shuo Li, Xiaoyu Xu, Kefan Du, Xinyu Shi, Rui Bian, Xiaohui Bo, Guochen Liu, Jun Luo, Jie Yang, Yi Cui, Rui Zhou, Jinchen Wang, Rong Yu, Weiqiang Yu. 2026-03-04. NMR evidence of spin supersolid and Pomeranchuk effect behaviors in the triangular-lattice antiferromagnet Rb$_2$Ni$_2$(SeO$_3$)$_3$. https://doi.org/10.1088/0256-307x/43/4/040709

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