Spin-phonon-charge coupling in the two-dimensional honeycomb lattice compound <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Ni</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Te</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:mrow></mml:math>
Ajay Tiwari, D. Chandrasekhar Kakarla, Bommareddy Poojitha, Priyambada Sahoo, Hsiang‐Lin Liu, Ambesh Dixit, Chin‐Wei Wang, T. W. Yen, M.-J. Hsieh, J.-Y. Lin, Jyothinagaram Krishnamurthy, Yen‐Chung Lai, Hsiung Chou, T. W. Kuo, Arkadeb Pal, H. D. Yang
Abstract
A two-dimensional honeycomb-structured magnet ${\mathrm{Ni}}_{2}{\mathrm{Te}}_{3}{\mathrm{O}}_{8}$ was synthesized, characterized, and comprehensively investigated for its intriguing physical properties. DC magnetization, specific heat, and neutron diffraction revealed a long-range commensurate antiferromagnetic ordering at ${T}_{\mathrm{N}}\ensuremath{\sim}35\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ with a propagation vector $\mathbf{k}=(100)$. The magnetic sublattice comprises stacking distorted honeycomb layers along the $a$ axis. The ${\mathrm{Ni}}^{2+}$ spins on the honeycomb lattice are essentially pointing out of the layers and are antiferromagnetically coupled to the neighboring spins. Temperature ($T$) and magnetic field ($H$) dependent dielectric measurements indicated an apparent anomaly near ${T}_{\mathrm{N}}$, accompanied by a weak magnetodielectric effect. Raman mode renormalization and lattice anomalies near ${T}_{\mathrm{N}}$ demonstrated spin-lattice coupling through magnetoelastic and spin-phonon interactions. These findings highlight the fascinating interplay between spin, charge, and phonon degrees of freedom in ${\mathrm{Ni}}_{2}{\mathrm{Te}}_{3}{\mathrm{O}}_{8}$.