Tunable magnetism and electron correlation in Titanium-based Kagome metals RETi3Bi4 (RE = Yb, Pr, and Nd) by rare-earth engineering

TL;DR

This study introduces a new family of Titanium-based Kagome metals RETi3Bi4, demonstrating how rare-earth element substitution tunes magnetic states and electron correlations, offering a platform for exploring topological and exotic quantum phases.

Contribution

The paper reports the discovery and characterization of RETi3Bi4 compounds with tunable magnetic and electronic properties through rare-earth engineering.

Findings

Magnetic states vary from nonmagnetic to ferromagnetic with different RE atoms.

Electron correlation and density of states evolve with rare-earth substitution.

High-pressure resistance measurements suggest a link between electron correlation and magnetic ordering.

Abstract

Rare-earth engineering is an effective way to introduce and tune the magnetism in topological Kagome magnets, which has been acting as a fertile platform to investigate the quantum interactions between geometry, topology, spin, and correlation. Here we report the structure and properties of three newly discovered Titanium-based Kagome metals RETi3Bi4 (RE = Yb, Pr, and Nd) with various magnetic states. They crystalize in the orthogonal space group Fmmm (No.69), where slightly distorted Ti Kagome lattice, RE triangular lattice, Bi honeycomb and triangular lattices stack along the a axis. By changing the rare earth atoms on RE zag-zig chains, the magnetism can be tuned from nonmagnetic YbTi3Bi4 to short-range ordered PrTi3Bi4 (Tanomaly ~ 8.2 K), and finally to ferromagnetic NdTi3Bi4 (Tc ~ 8.5 K). The measurements of resistivity and specific heat capacity demonstrate an evolution of electron correlation and density of states near the Fermi level with different rare earth atoms. In-situ resistance measurements of NdTi3Bi4 under high pressure further reveal a potential relationship between the electron correlation and ferromagnetic ordering temperature. These results highlight RETi3Bi4 as another family of topological Kagome magnets to explore nontrivial band topology and exotic phases in Kagome materials.