"Fractionalized excitations probed by ultrasound" Dr. S. Zherlitsyn

Jan 24, 2025

講演題目: Fractionalized excitations probed by ultrasound

講師: Dr. Sergei Zherlitsyn

Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden, Germany

日時: 2025年1月24日（金）17:00-18:00

場所: 北海道大学理学部 2-221室　＋ZOOM（ハイブリッド）共催　日本物理学会北海道支部講演会

要旨: We study magnetoelastic interactions by means of ultrasound experiments in α-RuC_l3 — a prototypical material for the Kitaev spin model on the honeycomb lattice, with a possible spin-liquid state featuring Majorana fermions and Z₂-flux excitations [1]. 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. Furthermore, we investigate the effects of hydrostatic pressure on α-RuC_l3 and reveal significant modifications of the acoustic properties and the H-T phase diagram of this material [2]. Above 0.28 GPa, the sound attenuation becomes nearly temperature-independent, suggesting a shift in the phonon scattering regime dominated by Majorana fermions. We demonstrate the potential of phonon dynamics as a promising probe for uncovering fractionalized excitations in α-RuC_l3.

[1]. A. Hauspurg, S. Zherlitsyn, T. Helm, V. Felea, J. Wosnitza, V. Tsurkan, K.-Y. Choi, S.-H. Do, Mengxing Ye, W. Brenig, and N. B. Perkins, Phys. Rev. B 109, 144415 (2024).
[2]. A. Hauspurg, S. Singh, T. Yanagisawa, V. Tsurkan, J. Wosnitza, W. Brenig, N. B. Perkins, and S. Zherlitsyn, in preparation.

世話人：　 柳澤達也（大学院理学研究院）
tatsuya@phys.sci.hokudai.ac.jp