Tuning of magnetic quantum criticality in artificial Kondo superlattice CeRhIn5/YbRhIn5

TL;DR

This study investigates how reducing dimensionality and interface effects in artificial Kondo superlattices of CeRhIn5/YbRhIn5 can tune magnetic quantum criticality, revealing a quantum critical point at a specific layer thickness influenced by spin-orbit interactions.

Contribution

It demonstrates the control of quantum criticality through layer thickness and interface effects, highlighting the role of Rashba spin-orbit interaction in tuning magnetic properties in Kondo superlattices.

Findings

Quantum critical point reached at n=3 layers.

Suppression of Kondo coherence temperature with reduced layers.

Opposite anisotropy of quantum critical field due to interface effects.

Abstract

The effects of reduced dimensions and the interfaces on antiferromagnetic quantum criticality are studied in epitaxial Kondo superlattices, with alternating $n$ layers of heavy-fermion antiferromagnet CeRhIn$_5$ and 7 layers of normal metal YbRhIn$_5$. As $n$ is reduced, the Kondo coherence temperature is suppressed due to the reduction of effective Kondo screening. The N\'{e}el temperature is gradually suppressed as $n$ decreases and the quasiparticle mass is strongly enhanced, implying dimensional control toward quantum criticality. Magnetotransport measurements reveal that a quantum critical point is reached for $n=3$ superlattice by applying small magnetic fields. Remarkably, the anisotropy of the quantum critical field is opposite to the expectations from the magnetic susceptibility in bulk CeRhIn$_5$, suggesting that the Rashba spin-orbit interaction arising from the inversion symmetry breaking at the interface plays a key role for tuning the quantum criticality in the two-dimensional Kondo lattice.