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arXiv · 2311.03231

Repulsive Tomonaga-Luttinger Liquid in Quasi-one-dimensional Alternating Spin-$1/2$ Antiferromagnet NaVOPO$_4$

S. S. Islam·Prashanta K. Mukharjee·P. K. Biswas·Mark Telling·Y. Skourski·K. M. Ranjith·M. Baenitz·Y. Inagaki·Y. Furukawa·A. A. Tsirlin·R. Nath
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Abstract

We probe the magnetic field-induced Tomonaga-Luttinger liquid (TLL) state in the bond-alternating spin-$1/2$ antiferromagnetic (AFM) chain compound NaVOPO$_4$ using thermodynamic as well as local $\mu$SR and $^{31}$P NMR probes down to milli-K temperatures in magnetic fields up to 14~T. The $\mu$SR and NMR relaxation rates in the gapless TLL regime decay slowly following characteristic power-law behaviour, enabling us to directly determine the interaction parameter $K$ as a function of the magnetic field. These estimates are cross-checked using magnetization and specific heat data. The field-dependent $K$ lies in the range of $0.4 < K < 1$ and indicates repulsive nature of interactions between the spinless fermions, in line with the theoretical predictions. This renders NaVOPO$_4$ the first experimental realization of TLL with repulsive fermionic interactions in hitherto studied $S=1/2$ bond-alternating AFM-AFM chain compounds.

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S. S. Islam, Prashanta K. Mukharjee, P. K. Biswas, Mark Telling, Y. Skourski, K. M. Ranjith, M. Baenitz, Y. Inagaki, Y. Furukawa, A. A. Tsirlin, R. Nath. 2023-11-06. Repulsive Tomonaga-Luttinger Liquid in Quasi-one-dimensional Alternating Spin-$1/2$ Antiferromagnet NaVOPO$_4$. https://arxiv.org/abs/2311.03231

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