Fingerprinting Triangular-Lattice Antiferromagnet by Excitation Gaps

TL;DR

This study investigates the magnetic excitation gaps in CeCd$_3$As$_3$, a rare-earth triangular-lattice antiferromagnet, using field-dependent heat capacity measurements to understand its magnetic state and develop a quantitative microscopic model.

Contribution

It provides a detailed, quantitative analysis of excitation gap evolution in CeCd$_3$As$_3$, constraining its microscopic pseudo-spin model and clarifying its magnetic order.

Findings

Field-dependent heat capacity reveals excitation gap evolution.

Model constrains the pseudo-spin interactions and magnetic order.

Provides a paradigm for rare-earth triangular-lattice systems.

Abstract

CeCd$_3$As$_3$ is a rare-earth triangular-lattice antiferromagnet with large inter-layer separation. Our field-dependent heat capacity measurements at dilution fridge temperatures allow us to trace the field-evolution of the spin-excitation gaps throughout the antiferromagnetic and paramagnetic regions. The distinct gap evolution places strong constraints on the microscopic pseudo-spin model, which, in return, yields a close {\it quantitative} description of the gap behavior. This analysis provides crucial insights into the nature of the magnetic state of CeCd$_3$As$_3$, with a certainty regarding its stripe order and low-energy model parameters that sets a compelling paradigm for exploring and understanding the rapidly growing family of the rare-earth-based triangular-lattice systems.