Weak Antilocalization and Quantum Oscillations of Surface States in Topologically Nontrivial DyPdBi(110)Half Heusler alloy.

ABSTRACT: Recently, a number of ternary half-Heusler compounds have been predicted independently by several research groups as candidates for 3D topological insulators. In this work, we report the observation of a two-dimensional (2D) weak antilocalization (WAL) effect, one of the hall-marks of topological surface states, and Shubnikov-de Hass (SdH) quantum oscillations in <110> oriented DyPdBi (DPB) thin films grown on MgO (100) substrates. The films prepared by pulsed laser deposition technique under the optimized conditions, showed a textured structure with (110) planes parallel to the (100) plane of MgO. The measured WAL effect follows the Hikami-Larkin-Nagaoka (HLN) model and the extracted values of phase coherence length (l_?) and ? are ~420?nm and ~-0.52 respectively. The power law variation of l_? (~T^-0.46) indicates the presence of the 2D surface states in DPB film. The Dirac nature of the surface states is further confirmed by Landau-level fan diagram analysis of SdH oscillations of the magneto-transport data. This analysis shows a finite Berry phase of 0.90??±?0.16, reasonably close to the expected ? value. Sheet Carrier density, n_s?~?2.56?×?10¹²?cm^-2, calculated from the SdH oscillations (f_SdH?~?106?T) and Hall measurements agree well with each other. These findings demonstrate that the half Heusler DPB thin films (~15-20?nm) can be used as a suitable material for investigating the novel intrinsic quantum transport properties of surface Dirac fermions.

SUBMITTER: Bhardwaj V 

PROVIDER: S-EPMC6028386 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature