Comparison of Two Different Synthesis Methods of Single Crystals of Superconducting Uranium Ditelluride

Single crystal specimens of the actinide compound uranium ditelluride, UTe2, are of great importance to the study and characterization of its dramatic unconventional superconductivity, believed to entail spin-triplet electron pairing. A variety in the superconducting properties of UTe2 reported in the literature indicates that discrepancies between synthesis methods yield crystals with different superconducting properties, including the absence of superconductivity entirely. This protocol describes a process to synthesize crystals that exhibit superconductivity via chemical vapor transport, which has consistently exhibited a superconducting critical temperature of 1.6 K and a double transition indicative of a multi-component order parameter. This is compared to a second protocol that is used to synthesize crystals via the molten metal flux growth technique, which produces samples that are not bulk superconductors. Differences in the crystal properties are revealed through a comparison of structural, chemical, and electronic property measurements, showing that the most dramatic disparity occurs in the low-temperature electrical resistance of the samples.

Automated summary

The superconducting properties of uranium ditelluride UTe2 are influenced by synthesis methods, with some crystals potentially lacking superconductivity entirely. Crystals synthesized via chemical vapor transport exhibit a superconducting critical temperature of 1.6 K, while those synthesized via molten metal flux growth technique are not bulk superconductors. Measurements of structural, chemical, and electronic properties reveal significant differences in crystal properties, particularly in low-temperature electrical resistance.