Recent advances in microfocused angle-resolved photoemission (micro-ARPES) enable the investigation of momentum-resolved electronic structure on micron length scales. This thesis uses these capabilities to study three different quantum materials: bulk 1T-TaSe₂, strained La_2-xSr_xCuO₄ (LSCO) and Tl₂Ba₂CuO_6+δ (Tl2201).

In the charge-density wave system 1T-TaSe₂, we resolve coexisting insulating and metallic areas. Comparison with DMFT calculations indicate that the diverse electronic behavior is primarily dictated by the stacking arrangement while correlation effects play a secondary role. These results reconcile conflicting previous reports.

Straining LSCO we achieve a significant electronic anisotropy resulting in a splitting of the van Hove singularity at orthogonal boundaries of the Brillouin zone. The modified electronic structure results in an enhancement of the pseudogap in combination with a suppression of superconductivity. Finally, we explore focused ion beam micro-fabrication to cleave the structurally three-dimensional Tl2201 and present first ARPES results.