UOTe: Kondo-interacting topological antiferromagnet in a van der Waals lattice

TL;DR

This paper reports the discovery of UOTe, a van der Waals material that intrinsically combines magnetism, topological electronic structure, and strong electron correlations, featuring a high AFM transition temperature and Kondo interactions.

Contribution

It introduces UOTe as the first vdW material hosting all three properties—magnetism, topology, and correlations—demonstrating AFM Dirac semimetal behavior and potential as a fully-compensated AFM Chern insulator.

Findings

UOTe exhibits a high AFM transition temperature of 150 K.

ARPES measurements reveal Dirac bands near the Fermi level.

Kondo interactions are evidenced by a 5f flat band below 100 K.

Abstract

Since the initial discovery of two-dimensional van der Waals (vdW) materials, significant effort has been made to incorporate the three properties of magnetism, band structure topology, and strong electron correlations $-$ to leverage emergent quantum phenomena and expand their potential applications. However, the discovery of a single vdW material that intrinsically hosts all three ingredients has remained an outstanding challenge. Here we report the discovery of a Kondo-interacting topological antiferromagnet in the vdW 5$f$ electron system UOTe. It has a high antiferromagnetic (AFM) transition temperature of 150 K, with a unique AFM configuration that breaks the combined parity and time reversal ($PT$) symmetry in an even number of layers while maintaining zero net magnetic moment. Our angle-resolved photoemission spectroscopy (ARPES) measurements reveal Dirac bands near the Fermi level, which combined with our theoretical calculations demonstrate UOTe as an AFM Dirac semimetal. Within the AFM order, we observed the presence of the Kondo interaction, as evidenced by the emergence of a 5$f$ flat band near the Fermi level below 100 K and hybridization between the Kondo band and the Dirac band. Our density functional theory calculations in its bilayer form predict UOTe as a rare example of a fully-compensated AFM Chern insulator.