Chemical Pressure Effect in Distorted Kagome Lattice Magnetic Topological Candidates

Magnetic topological semimetals are an exciting class of quantum materials in which the electronic wavefunction coupled magnetic spin configuration is greatly influenced by the topology of the compounds. A prototypical geometrically frustrated system is the kagome lattice, which provides an ideal platform for exploring candidate topological semimetals due to the unique interplay of geometric frustration, spin-orbit coupling, and strong correlations. The kagome lattice can host noncollinear and noncoplanar spin textures that can induce topological magnetic states which give rise to the quantum anomalous Hall effect and Weyl semimetallic behavior. Recent attention has been given to the REAgGe (RE= rare earth) family of materials, with noncentrosymmetric P-62m space group, which hosts a distorted kagome lattice in the network of rare-earth ions. Here we utilize chemical pressure to tune the kagome lattice distortion and spin configurations, and in turn the nontrivial topological states. We have successfully synthesized Si doped single crystalline REAgGe materials as determined by X-ray diffraction and SEM-EDX techniques. The partial substitution of the smaller Si atoms for the larger Ge atoms creates a positive chemical pressure effect reducing the lattice dimensions. The magnetization data reveals a potential influence of the chemical pressure effect on the metamagnetic states in these materials. These results will ultimately lead to a better understanding of the interplay between magnetism and topology.