Date of Graduation

5-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Materials Science & Engineering (PhD)

Degree Level

Graduate

Department

Materials Science & Engineering

Advisor/Mentor

Jin Hu

Committee Member

Hugh Churchill

Second Committee Member

Shui-Qing Yu

Third Committee Member

Salvador Barraza-Lopez

Fourth Committee Member

Matthew Leftwich

Keywords

Condensed matter physics, Magnetic topological semimetals, Quantum materials

Abstract

The demand for energy-efficient devices has been growing rapidly due to the need for data-driven technologies and the global energy crisis. As device size approaches the atomic scale, the miniaturization of electronic devices may stop in the near future unless fundamentally new materials or device concepts are developed. The emergent topological materials with exotic properties show remarkable robustness against crystal lattice defects, which are promising for next-generation technology. These materials host exotic properties such as high mobility, large magnetoresistance, chiral anomaly, and surface Fermi arcs, etc. Among various topological materials, the ZrSiS-family materials exhibit two types of Dirac states, which provide opportunities to tune topological states by varying different parameters. The magnetic version of ZrSiS-family compounds, LnSbTe (Ln = lanthanide), hosts inherent magnetism, providing a novel platform to study the interplay between magnetism and exotic quantum states.With this motivation, this research is focused on the synthesis of single-crystal and characterization of previously unexplored magnetic topological nodal line semimetals LnSbTe. The compounds NdSbTe and SmSbTe exhibit antiferromagnetic ground states and enhanced electronic correlations. The magnetization and heat capacity measurements suggest the possible existence of magnetic frustration in tetragonally crystallized SmSbTe. Furthermore, the evolution of electronic and magnetic properties was studied with varying composition.

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