Prevailing orbital excitations in paramagnetic kagome superconductor Cs(V$_{0.95}$Ti$_{0.05}$)$_3$Sb$_5$

Chennan Wang; Yuhang Zhang; Zhen Zhao; Zhouyouwei Lu; Hui Chen; Ziqiang Wang; Haitao Yang; Christian Bernhard; Xiaoli Dong; Hong-Jun Gao

arXiv · 2511.05999

Prevailing orbital excitations in paramagnetic kagome superconductor Cs(V$_{0.95}$Ti$_{0.05}$)$_3$Sb$_5$

Chennan Wang·Yuhang Zhang·Zhen Zhao·Zhouyouwei Lu·Hui Chen·Ziqiang Wang·Haitao Yang·Christian Bernhard·Xiaoli Dong·Hong-Jun Gao

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Abstract

Using the muon as a sensitive local magnetic probe, we investigated the layered kagome superconductor Cs(V$_{0.95}$Ti$_{0.05}$)$_3$Sb$_5$, a material notably devoid of both static magnetic moments and long-range charge order. Our transverse-field $\mu$SR measurements reveal that the local magnetic susceptibility, obtained via the muon Knight shift, is dominated by orbital excitations with a split energy levels around 20 meV. Meanwhile, the persistence of itinerant electron paramagnetism down to 5 K and 7 T confirms the absence of static magnetism within this regime. In addition, zero-field (ZF) $\mu$SR experiments detect a significant increase in the inhomogeneous nuclear dipolar field distribution below a featured temperature at 70 K. We attribute this ZF-$\mu$SR feature to the emergence of local lattice distortions at low temperatures, potentially arising from orbital ordering. Significantly, our study establishes that orbital excitations constitute an intrinsic property of the layered V-Sb kagome lattice. Despite its small magnitude, spin-orbit coupling plays a crucial role in governing the lattice dynamics, potentially driving the emergence of novel phenomena such as phonon carrying angular momentum in crystals with non-chiral point groups.

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Chennan Wang, Yuhang Zhang, Zhen Zhao, Zhouyouwei Lu, Hui Chen, Ziqiang Wang, Haitao Yang, Christian Bernhard, Xiaoli Dong, Hong-Jun Gao. 2025-11-08. Prevailing orbital excitations in paramagnetic kagome superconductor Cs(V$_{0.95}$Ti$_{0.05}$)$_3$Sb$_5$. https://arxiv.org/abs/2511.05999

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