Here we present a neutron scattering-based study of magnetic excitations and magnetic order in NaYbO2 under the application of an external magnetic field. The crystal electric field-split J=7/2 multiplet structure is determined, revealing a mixed ∣mz> ground state doublet and is consistent with a recent report Ding et al. [1]. Our measurements further suggest signatures of exchange effects in the crystal field spectrum, manifested by a small splitting in energy of the transition into the first excited doublet. The field-dependence of the low-energy magnetic excitations across the transition from the quantum disordered ground state into the fluctuation-driven ordered regime is analyzed. Signs of a first-order phase transition into a noncollinear ordered state are revealed at the upper-field phase boundary of the ordered regime, and higher order magnon scattering, suggestive of strong magnon-magnon interactions, is resolved within the previously reported up−up−down phase. Our results reveal a complex phase diagram of field-induced order and spin excitations within NaYbO2 and demonstrate the dominant role of quantum fluctuations cross a broad range of fields within its interlayer frustrated triangular lattice.
@article{arxiv.2005.10375,
title = {Spin excitations in the frustrated triangular lattice antiferromagnet NaYbO$_2$},
author = {Mitchell Bordelon and Chunxiao Liu and Lorenzo Posthuma and P. M. Sarte and N. P. Butch and Daniel M. Pajerowski and Arnab Banerjee and Leon Balents and Stephen D. Wilson},
journal= {arXiv preprint arXiv:2005.10375},
year = {2020}
}