Quantum Phases of the Shastry-Sutherland Kondo Lattice: Implications for the Global Phase Diagram of Heavy Fermion Metals

TL;DR

This paper explores the complex interplay of magnetic frustration and Kondo interactions in the Shastry-Sutherland lattice, revealing phase diagrams that inform understanding of heavy fermion materials and quantum criticality.

Contribution

It provides a theoretical phase diagram for the Shastry-Sutherland Kondo lattice, connecting magnetic frustration and Kondo coupling, with implications for experimental heavy fermion systems.

Findings

Identification of valence bond solid and heavy Fermi liquid phases.

Zero-temperature phase diagram similar to the global phase diagram.

Relevance to experiments on Yb$_2$Pt$_2$Pb and related compounds.

Abstract

Considerable recent theoretical and experimental efforts have been devoted to the study of quantum criticality and novel phases of antiferromagnetic heavy-fermion metals. In particular, quantum phase transitions have been discovered in the compound Yb$_2$Pt$_2$Pb. These developments have motivated us to study the competition between the RKKY and Kondo interactions on the Shastry-Sutherland lattice. We determine the zero-temperature phase diagram as a function of magnetic frustration and Kondo coupling within a slave-fermion approach. Pertinent phases include the Shastry-Sutherland valence bond solid and heavy Fermi liquid. In the presence of antiferromagnetic order, our zero-temperature phase diagram is remarkably similar to the global phase diagram proposed earlier based on general grounds. We discuss the implications of our results for the experiments on Yb$_2$Pt$_2$Pb and other geometrically frustrated heavy fermion compounds.