Superconductivity and strong spin-orbit coupling in a new noncentrosymmetric compound ThIrP

A new noncentrosymmetric phosphide ThIrP has been synthesized and characterized. X-ray diffraction analysis shows that this compound crystallizes in a LaPtSi-type tetragonal lattice (space group I4(1)md, Z = 4), whose lattice parameters are a = b = 4.0676(1) angstrom, c = 14.3354(2) angstrom, and V = 237.191(8) angstrom(3). Moreover, ThIrP is discovered to be an intermediately coupled, type-II superconductor with possibly multiple gaps below T-c = 5.07 K. The upper critical magnetic field, Sommerfield coefficient, and Ginzburg-Laudau parameter are determined based on physical property measurements, which are B-c2 = 0.83 T, gamma = 7.5 mJ mol(-1) K-2, and kappa(GL) = 7.5, respectively. The electronic band structure calculations point out nearly equal contributions of Ir and Th atoms on the density of states around the Fermi surface. In addition, the spin-orbit coupling induced band splitting reaches as large as 270 meV along the Gamma-Z line. Our results suggest that ThIrP provides a platform to study the interplay between inversion-symmetry breaking, strong spin-orbit coupling, and superconductivity.

Automated summary

A new noncentrosymmetric phosphide ThIrP has been synthesized and characterized, exhibiting intermediate coupling and type-II superconducting properties with possibly multiple gaps below the critical temperature. Physical property measurements have determined the upper critical magnetic field, Sommerfield coefficient, and Ginzburg-Laudau parameter of the compound.