Enhanced two-dimensional ferromagnetism in van der Waals $\beta$-UTe$_3$ monolayers

TL;DR

This paper reports the exfoliation of actinide $eta$-UTe$_3$ into monolayers, revealing strong electronic correlations and enhanced ferromagnetism at 35 K, making it a promising platform for studying 2D correlated quantum phenomena.

Contribution

It demonstrates that $eta$-UTe$_3$ can be exfoliated to monolayers, exhibiting strong correlations and increased ferromagnetic ordering temperature, a significant advancement in 2D metallic magnetic materials.

Findings

$eta$-UTe$_3$ can be exfoliated to monolayers.

Monolayer $eta$-UTe$_3$ shows strong electronic correlations.

Ferromagnetic order persists in monolayer with $T_C$ of 35 K.

Abstract

The discovery of local-moment magnetism in van der Waals (vdW) semiconductors down to the single-layer limit has led to a paradigm shift in the understanding of two-dimensional (2D) magnets and unleashed their potential for applications in microelectronic and optoelectronic devices. The incorporation of strong electronic and magnetic correlations in 2D vdW metals remains a sought-after platform not only to enable control of emergent quantum phases, such as superconductivity, but also to achieve more theoretically tractable microscopic models of complex materials. To date, however, there is limited success in the discovery of such metallic vdW platforms, and $f$-electron monolayers remain out of reach. Here we demonstrate that the actinide $\beta$-UTe$_3$ can be exfoliated to the monolayer limit. A sizable electronic specific heat coefficient provides the hallmark of strong correlations. Remarkably, $\beta$-UTe$_3$ remains ferromagnetic in the half-unit-cell limit with an enhanced ordering temperature of 35 K, a factor of two larger than its bulk counterpart. Our work establishes $\beta$-UTe$_3$ as a novel materials platform for investigating and modeling correlated behavior in the monolayer limit and opens numerous avenues for quantum control with, e.g., strain engineering.