Superconductivity in LaRhGa with Noncentrosymmetric Structure.

We report here on the discovery of the superconductivity of a new ternary compound LaRhGa, which possesses a CaBeGe-type structure. Electrical resistivity and magnetic susceptibility measurements reveal that LaRhGa undergoes a superconducting transition at 3.7 K and exhibits type-II superconductivity. The -linear behavior of the upper critical field is likely induced by the two-gap superconducting state because of its structural features (i.e., its noncentrosymmetric structure). A transition at of specific heat suggested that the LaRhGa is a weak electron-phonon-mediated superconductor. Comparison with a related superconductor demonstrates that there is an important factor other than electron-phonon coupling strength that induces higher in the LaTMGa system with a noncentrosymmetric CaBeGe-type structure.