Growth conditions, stoichiometry and the superconducting properties of UTe2

Uranium ditelluride (UTe2) shows several hallmarks of spin-triplet superconductivity, including ultra-high critical fields beyond the Pauli limit and miniscule Knight shift through the superconducting transition. However, the superconducting state in UTe2 has, for the most part, not displayed the exquisite sensitivity to disorder that is expected in triplet superconductors. In this talk I will review the differences in superconducting properties grown under different conditions and our ongoing attempts to control them. I will then present data from electrical and thermal transport, along with heat capacity and elemental analysis, that provide multiple evaluations of the cleanliness of these different samples. Finally, I will discuss how these different measures of cleanliness correlate with the key superconducting properties of UTe2 and how these observations inform the emerging picture of superconductivity in this system.