UC Davis

In this dissertation, I will describe two experimental studies on two different condensed matter systems. The first study originates from our crystallographic findings on LaNiGa2. After developing a single crystal synthesis method, single-crystal X-ray diffraction results improve upon previous studies by showing that LaNiGa2 crystallizes in a Cmcm unit cell instead of a Cmmm one. As a result of uncovering nonsymmorphic symmetry operations, we show that these directly result in two topological features precisely at the Fermi level. With the previous knowledge that LaNiGa2 breaks time-reversal symmetry within its superconducting state and shows evidence for multi-gap superconducting behavior, we can then directly connect the new crystallographic results, the topological features, and the unique superconducting state.

In the second study, we synthesize and then characterize single crystals of Nd substituted CeIn3. This well-studied heavy-fermion system has previously exhibited fascinating phenomena as its antiferromagnetic ordering is systematically suppressed. In Ce1-xNdxIn3 we reveal an interesting interplay between the Kondo lattice coherence and crystal electric field depopulation effects. Wherein we can separate the two features in electrical resistivity measurements in the most disordered substitution range of x=0.4-0.5. We also reveal a comprehensive phase diagram between the two antiferromagnetic ordering.

In addition to these two studies, I also provide an overview of relevant concepts and experimental techniques. The purpose of this overview is to provide incoming graduate students a starting point to begin to understand what principles are relevant to the condensed matter systems discussed in this dissertation and how to perform specific experimental techniques to study said principles. Within the experimental section, I also provide some ``experimentalist's insights'' on the techniques I have used extensively throughout my graduate work.