# Orbital-selective Kondo entanglement and antiferromagnetic order in USb$_2$

## TL;DR

This study uses angle-resolved photoemission spectroscopy to reveal orbital-selective Kondo entanglement and magnetic order in USb$_2$, highlighting the complex interplay of electronic states in heavy-fermion materials.

## Contribution

It uncovers orbital-dependent electronic states in USb$_2$ and demonstrates their distinct roles in Kondo correlations and magnetic order, advancing understanding of correlated $f$ electron systems.

## Key findings

- Identification of two nearly flat bands with different orbital characters.
- Observation of temperature-dependent Kondo-driven and magnetically dominated states.
- Implication of orbital selectivity as a key factor in the competition between Kondo effect and magnetic order.

## Abstract

In heavy-fermion compounds, the dual character of $f$ electrons underlies their rich and often exotic properties like fragile heavy quasipartilces, variety of magnetic orders and unconventional superconductivity. 5$f$-electron actinide materials provide a rich setting to elucidate the larger and outstanding issue of the competition between magnetic order and Kondo entanglement and, more generally, the interplay among different channels of interactions in correlated electron systems. Here, by using angle-resolved photoemission spectroscopy, we present detailed electronic structure of USb$_2$ and observed two different kinds of nearly flat bands in the antiferromagnetic state of USb$_2$. Polarization-dependent measurements show that these electronic states are derived from 5$f$ orbitals with different characters; in addition, further temperature-dependent measurements reveal that one of them is driven by the Kondo correlations between the 5$f$ electrons and conduction electrons, while the other reflects the dominant role of the magnetic order. Our results on the low-energy electronic excitations of USb$_2$ implicate orbital selectivity as an important new ingredient for the competition between Kondo correlations and magnetic order and, by extension, in the rich landscape of quantum phases for strongly correlated $f$ electron systems.