Time: 15:00, Sep. 13, 2021(Beijing/Shanghai Time)

Zoom Meeting ID：949 559 7503

Password：2021

Meeting URL: https://us06web.zoom.us/j/9495597503?pwd=UFVMUUVxb3pDUHRkWEFQY3MzRjJYUT09

Speaker: Hui-Ke Jin (TU Munich)

Abstract：

The S=3/2 Kitaev honeycomb model (KHM) has defied an analytical as well as numerical understanding because it is not exactly soluble like its S=1/2 brethren and in contrast to other spin-S Kitaev models numerical methods are plagued by a massive pile up of low energy states. Here, we uncover the phase diagram of the S=3/2 KHM and find gapped and gapless quantum spin liquids (QSLs) generally coexisting with spin quadrupolar orders. Employing an SO(6) Majorana fermion representation of spin-3/2’s, we find an exact representation of the conserved plaquette fluxes in terms of static Z2 gauge fields akin to the S=1/2 KHM which enables us to treat the remaining interacting matter fermion sector in a parton mean-field theory. The latter provides an explanation for the extensive near degeneracy of low energy states in the gapless phase via the appearance of almost flat Majorana bands close to zero energy. Our parton description is in remarkable quantitative agreement with numerical simulations using the density matrix renormalization group method, and is furthermore corroborated by the addition of a single ion anisotropy which continuously connects the gapless Dirac QSL of our model with that of the S=1/2 KHM. We discuss the implications of our findings for materials realization of higher S=3/2 KHMs and the stability of the QSL phase with respect to additional interactions.

arXiv:2107.13364

About the speaker：

Hui-Ke Jin did his Ph.D. in theoretical physics at Zhejiang University from 2015 to 2020. His Ph.D. supervisors are Prof. Yi Zhou and Prof. Fu-Chun Zhang. He also worked in KITS, Beijing, as a visiting student from 2018 to 2020. After his Ph.D., he moved to TU Munich, Germany, to start his postdoc research. His research interests include quantum magnetism, tensor network states, and topological phase of matter.