Dynamical properties of fractional excitations in Kitaev spin liquids

Yasuhiro Shimizu, Yuya Nagai, Takaaki Jin-no +4 more

Johannes Knolle

譲治 那須, Joji Nasu, 幸年 求 +1 more

Shang-Shun Zhang, Gábor B. Halász, Wei Kang Zhu +1 more

We compute the low-energy excitation spectrum and the dynamical spin structure factor of the Kitaev-Heisenberg-Gamma model through a variational approach based on the exact fractionalized excitations of the pure Kitaev honeycomb model. This novel approach reveals the physical reason for the asymmetric stability of the Kitaev spin liquid phases around the ferromagnetic and antiferromagnetic Kitaev limits. Moreover, we demonstrate that the fractionalized excitations form bound states in specific regions of each Kitaev spin liquid phase and that certain phase transitions induced by Heisenberg and Gamma interactions are driven by the condensation of such a bound state. Remarkably, this bound state appears as a sharp mode in the dynamical spin structure factor, while its condensation patterns at the appropriate phase transitions provide a simple explanation for the magnetically ordered phases surrounding each Kitaev spin liquid phase.

Shuang Liang, Wei Chen

Joji Nasu, Yukitoshi Motome

This paper shows that two types of fractional quasiparticles in the Kitaev spin liquid are selectively excited with distinct time scales in the transient spin dynamics after quenching the magnetic field. The present result indicates that the real-time dynamics provides a promising route to the identification of spin fractionalization and would pave a way for the manipulation of fractional quasiparticles toward topological quantum computation in condensed matter.