Superconductivity in Th₃P₄-type noncentrosymmetric La₃Se₄

The thorium phosphide structure, Th₃P₄, occurs widely in the compounds of the lanthanides with selenium, sulfur and tellurium and have interesting electrical, superconducting or magnetic properties. Polycrystalline La₃Se₄ was synthesized via solid state reaction route. La₃Se₄ crystallizes in a noncentrosymmetric cubic Th₃P₄-type structure with space group: I-43d. Superconductivity with T_c~ 8.5 K has been confirmed from both the resistivity and magnetic susceptibility data. From the generalized Ginzburg-Landau model, the upper critical field H_c2(0) and coherence length ξ_GL(0) are found to be 8.09 T and 64 Å respectively. Superconductivity in noncentrosymmetric structures offer a wide ranging opportunites for the investigation of exotic properties.