霍普金斯大学 Shu "Suzy" Zhang, Johns Hopkins University

报告摘要：

To look for quantum spin liquid states in real materials, it is crucial to understand the dynamical signatures in their magnetic excitations. The spin-1 compound NaCaNi2F7[1] is an almost ideal realization of the antiferromagnetic Heisenberg model on a pyrochlore lattice, the classical version of which is predicted to be a spin liquid[2]. Indeed, the material doesn’t develop magnetic order down to 0.35K and the broad continuum observed in the inelastic neutron scattering experiment[3] indicates the absence of magnons with well-defined dispersions. We theoretically calculate the dynamical structure factor using three complementary methods: molecular dynamics, stochastic model and the linear spin wave theory. The results[4] reproduce well the momentum and energy dependence of the scattering intensity. This analysis leads to an intuitive picture of the spin dynamics in this frustrated magnet.

[1] J. W. Krizan and R. J. Cava, Phys. Rev. B 92, 014406 (2015)

[2] S. V. Isakov, K. Gregor, R. Moessner, and S. L. Sondhi, Phys. Rev. Lett. 93, 167204 (2004)

[3] K. W. Plumb, H. J. Changlani, A. Scheie, S. Zhang, J. W. Krizan, J. A. Rodriguez- Rivera, Y. Qiu, B. Winn, R. J. Cava and C. L. Broholm, Nat. Phys. 10.1038/s41567- 018-0317-3 (2018)

[4] S. Zhang, H. J. Changlani, K. W. Plumb, O. Tchernyshyov and R. Moessner, arXiv:1810.09481

联系人：万源 yuan.wan@iphy.ac.cn