Interleaved bond frustration in a triangular lattice antiferromagnet

TL;DR

This paper reports on a class of materials, $Ln$Cd$_3$P$_3$, that exhibit coexisting frustrated magnetic and bond networks in a dopable semiconductor, revealing complex interplay between magnetic and structural frustration.

Contribution

It identifies and characterizes a new class of materials with simultaneous frustrated magnetic and bond order, expanding understanding of frustration effects in semiconductors.

Findings

Presence of kagome ice bond correlations

Coexistence of frustrated magnetism and bond order

Potential for coupling magnetic and lattice states

Abstract

Frustration of long-range order via lattice geometries serves to amplify fluctuations of the order parameter and generate unconventional ground states that are highly sensitive to perturbations. Traditionally, this concept of geometric frustration is used to engineer unconventional magnetic states in a variety of materials; however, the charge degree of freedom and bond order can be similarly frustrated. Finding materials that host both frustrated magnetic and bond networks holds promise for engineering structural and magnetic states with the potential of coupling to one another via either the magnetic sector (via magnetic field) or via the lattice sector (via strain). In this paper, we identify an unusual instance of this coexistence in the triangular lattice antiferromagnetic compounds $Ln$Cd$_3$P$_3$ ($Ln$ = La, Ce, Pr, and Nd). These compounds feature two-dimensional planes of unique trigonal-planar CdP$_3$ units that manifest an underlying bond instability with its long-range ordering frustrated via emergent kagome ice bond correlations. Our results establish $Ln$Cd$_3$P$_3$ as a rare class of materials where frustrated magnetism across a tunable rare-earth triangular network is embedded within a dopable semiconductor with a frustrated bond order instability.