In this paper we report the synthesis, magnetization and heat capacity of the frustrated magnets \emph{A}ErSe2(\emph{A}=Na,K) which contain perfect triangular lattices of Er3+. The magnetization data suggests no long-range magnetic order exists in \emph{A}ErSe2(\emph{A}=Na,K), which is consistent with the heat capacity measurements. Large anisotropy is observed between the magnetization within the \emph{ab} plane and along the \emph{c} axis of both compounds. When the magnetic field is applied along \emph{ab} plane, anomalies are observed at 1.8 μB in NaErSe2 at 0.2 T and 2.1 μB in KErSe2 at 0.18 T. Unlike NaErSe2, a plateau-like field-induced metamagnetic transition is observed for H∥\emph{c} below 1 K in KErSe2. Two broad peaks are observed in the heat capacity below 10 K indicating possible crystal electric field(CEF) effects and magnetic entropy released under different magnetic fields. All results indicate that \emph{A}ErSe2 are strongly anisotropic, frustrated magnets with field-induced transition at low temperature. The lack of signatures for long-range magnetic order implies that these materials are candidates for hosting a quantum spin liquid ground state.
@article{arxiv.1911.12268,
title = {Synthesis, magnetization and heat capacity of triangular lattice materials NaErSe$_2$ and KErSe$_2$},
author = {Jie Xing and Liurukara D. Sanjeewa and Jungsoo Kim and William R. Meier and Andrew F. May and Qiang Zheng and Radu Custelcean and G. R. Stewart and Athena S. Sefat},
journal= {arXiv preprint arXiv:1911.12268},
year = {2019}
}