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Spin excitation spectra of the spin-1/2 triangular anisotropic Heisenberg antiferromagnets from tensor networks

Runze Chi, Institute of Physics, Academy of Science

Hosted by Xiaoliang Qi

Event Details:

Friday, September 2, 2022
3:30pm - 4:30pm PDT

Location

United States

Location

McCullough 335

Abstract

Investigation of dynamical excitations is difficult but crucial to the understanding of many exotic quantum phenomena discovered in quantum materials. This is particularly true for highly frustrated quantum antiferromagnets whose dynamical properties deviate strongly from theoretical predictions based on the spin wave or other approximations. In this talk, I will present the results of our recent large-scale numerical calculation on the dynamical correlation functions of the spin-1/2 triangular Heisenberg model using a state-of-the-art tensor network renormalization group method. The calculated results allow us to gain for the first time a comprehensive picture of the nature of spin excitation spectra in this highly frustrated quantum system. Moreover, it provides a quantitative account for all the key features of the dynamical spectra disclosed by inelastic neutron scattering measurements for Ba3CoSb2O9, revealing the importance of the interplay between low and high-energy excitations and its renormalization effect to the low-energy magnon bands and high-energy continuums. From the analysis of the projected and sublattice spin structural factors, we further identify the damped longitudinal Higgs modes and predict the spectral functions along three principal axes that can be verified by polarized neutron scattering experiments. In addition, we study the spectra' dependence on the anisotropic factor. The weak anisotropy dependency of spin excitation spectra suggests that it is a general feature of the triangular-lattice Heisenberg antiferromagnets.

Reference https://Arxiv.org/abs/2201.12121 

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