%0 Journal Article %1 PhysRevB.109.144415 %A Hauspurg, A. %A Zherlitsyn, S. %A Helm, T. %A Felea, V. %A Wosnitza, J. %A Tsurkan, V. %A Choi, K.-Y. %A Do, S.-H. %A Ye, Mengxing %A Brenig, Wolfram %A Perkins, Natalia B. %D 2024 %I American Physical Society %J Phys. Rev. B %K b %N 14 %P 144415 %R 10.1103/PhysRevB.109.144415 %T Fractionalized excitations probed by ultrasound %U https://link.aps.org/doi/10.1103/PhysRevB.109.144415 %V 109 %X In this work, we study magnetoelastic interactions by means of ultrasound experiments in $\alpha\ensuremath-RuCl_3$---a prototypical material for the Kitaev spin model on the honeycomb lattice, with a possible spin-liquid state featuring Majorana fermions and $Z_2$-flux excitations. We present results of the temperature and in-plane magnetic-field dependence of the sound velocity and sound attenuation for several longitudinal and transverse phonon modes propagating along high-symmetry crystallographic directions. A comprehensive data analysis above the magnetically ordered state provides strong evidence of phonon scattering by Majorana fermions. This scattering depends sensitively on the value of the phonon velocities relative to the characteristic velocity of the low-energy fermionic excitations describing the spin dynamics of the underlying Kitaev magnet. Moreover, our data displays a distinct reduction of anisotropy of the sound attenuation, consistent with the presence of thermally excited $Z_2$ visons. We demonstrate the potential of phonon dynamics as a promising probe for uncovering fractionalized excitations in $\alpha\ensuremath-RuCl_3$ and provide new insights into the $H\ensuremath-T$ phase diagram of this material.

@article{PhysRevB.109.144415, abstract = {In this work, we study magnetoelastic interactions by means of ultrasound experiments in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$---a prototypical material for the Kitaev spin model on the honeycomb lattice, with a possible spin-liquid state featuring Majorana fermions and ${\mathbb{Z}}_{2}$-flux excitations. We present results of the temperature and in-plane magnetic-field dependence of the sound velocity and sound attenuation for several longitudinal and transverse phonon modes propagating along high-symmetry crystallographic directions. A comprehensive data analysis above the magnetically ordered state provides strong evidence of phonon scattering by Majorana fermions. This scattering depends sensitively on the value of the phonon velocities relative to the characteristic velocity of the low-energy fermionic excitations describing the spin dynamics of the underlying Kitaev magnet. Moreover, our data displays a distinct reduction of anisotropy of the sound attenuation, consistent with the presence of thermally excited ${\mathbb{Z}}_{2}$ visons. We demonstrate the potential of phonon dynamics as a promising probe for uncovering fractionalized excitations in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$ and provide new insights into the $H\text{\ensuremath{-}}T$ phase diagram of this material.}, added-at = {2024-05-16T14:23:45.000+0200}, author = {Hauspurg, A. and Zherlitsyn, S. and Helm, T. and Felea, V. and Wosnitza, J. and Tsurkan, V. and Choi, K.-Y. and Do, S.-H. and Ye, Mengxing and Brenig, Wolfram and Perkins, Natalia B.}, biburl = {https://www.bibsonomy.org/bibtex/2cefa3aba93a57b341ff41cc8f80d8973/ctqmat}, day = 18, description = {Phys. Rev. B 109, 144415 (2024) - Fractionalized excitations probed by ultrasound}, doi = {10.1103/PhysRevB.109.144415}, interhash = {1dab25bf4ea4396dd62336e60c59c2ba}, intrahash = {cefa3aba93a57b341ff41cc8f80d8973}, journal = {Phys. Rev. B}, keywords = {b}, month = {04}, number = 14, numpages = {11}, pages = 144415, publisher = {American Physical Society}, timestamp = {2024-05-16T14:23:45.000+0200}, title = {Fractionalized excitations probed by ultrasound}, url = {https://link.aps.org/doi/10.1103/PhysRevB.109.144415}, volume = 109, year = 2024 }