Search for superconductivity in LaNiP2 (P = Bi, Sb) thin films grown by reactive molecular beam epitaxy

We have explored the possibility of using reactive molecular beam epitaxy (RMBE) as a synthesis technique for the search for arsenic free pnictide superconductors. High quality epitaxial thin films of LaNiBi2 were successfully grown on (1 0 0) MgO substrates by RMBE. The films were (0 0 l) oriented and the epitaxial nature of the films was confirmed by RHEED and X-ray diffraction measurements. The LaNiBi2 thin films grown on (1 0 0) MgO shows that the a-axis of the films were 45° rotated with respect to MgO. The Ni deficient films gave a Tc(0) of 3.1 K. We have successfully substituted Bi by Sb and have grown high quality epitaxial thin films of LaNiSb2. However, the LaNiSb2 thin films did not show any superconductivity down to 1.5 K.

► Reactive molecular beam epitaxy as a viable synthetic synthesis technique. ► Growth of superconducting epitaxial thin films of LaNiBi2 on MgO substrate. ► Thin film synthesis of LaNiSb2 by reactive MBE, successfully replacing Bi by Sb.