Structural and transport properties of Y_1-x(Dy)_xPdBi (0 ≤ x ≤ 1) topological semi-metallic thin films

We report the effect of 4f electron doping on structural, electrical, and magneto-transport properties of Dy doped half Heusler Y_1-x(Dy)_xPdBi (x = 0, 0.2, 0.5, and 1) thin films grown by pulsed laser deposition. The electrical transport measurements show a typical semi-metallic behavior in the temperature range of 3 K ≤ T ≤ 300 K and a sharp drop in resistivity at low temperatures (<3 K) for all the samples. Magneto-transport measurements and Shubnikov de-Hass oscillations at high magnetic fields demonstrate that for these topologically non-trivial samples, Dy doping induced variation of spin-orbit coupling strength and lattice density plays an active role in modifying the Fermi surface, carrier concentration, and the effective electron mass of massless carriers. There is a uniform suppression of the onset of superconductivity-like phenomena with increased Dy doping, which is possibly related to the increasing local exchange field arising from the 4f electrons in Dy. Our results indicate that we can tune various band structure parameters of YPdBi by f electron doping, and strained thin films of Y_1-x(Dy)_xPdBi show surface dominated relativistic carrier transport at low temperatures.