Discovery of superconductivity in AlB2-type hexagonal YGa2

A crystalline sample YGa2 with the AlB2-type hexagonal structure has been synthesized using the self-flux method. We measured electrical resistivity and specific heat down to 0.4 K and in fields up to 200 mT. The obtained data reveal type-II superconductivity. Unusual behaviour of the temperature dependence of upper critical field H ( c2)(T (c)) was attributed to the crystal twinning of two phases possessing close lattice parameters. We determined thermodynamic parameters in the superconducting and normal states of YGa2. DFT calculations indicated a large change in the Fermi velocity of carriers nearby cylinder-like structured Fermi surface along the Gamma - A line.

Automated summary

A crystalline sample YGa2 with the AlB2-type hexagonal structure was synthesized using the self-flux method. Experimental measurements showed type-II superconductivity in the sample, with the unusual behavior of temperature dependence of the upper critical field H(c2)(T(c)) attributed to crystal twinning. DFT calculations indicated a significant change in the Fermi velocity of carriers near the cylinder-like structured Fermi surface along the Gamma - A line.