Exploration of growth conditions of TaAs Weyl semimetal thin film using pulsed laser deposition

Abstract

TaAs, the first experimentally discovered Weyl semimetal material, has attracted a lot of attention due to its high carrier mobility, high anisotropy, nonmagnetic properties and strong interaction with light. These make it an ideal candidate for the study of Weyl fermions and applications in quantum computation, thermoelectric devices, and photodetection. For further basic physics studies and potential applications, large-size and high-quality TaAs films are urgently needed. However, it is difficult to grow As-stoichiometry TaAs films due to the volatilization of As during the growth. To solve this problem, we attempted to grow TaAs films on different substrates using targets with different As stoichiometric ratios via pulsed laser deposition (PLD). In this work, we found that partial As ions of the GaAs substrate are likely to diffuse into the TaAs films during growth, which was preliminarily confirmed by structural characterization, surface topography and composition analysis. As a result, the As content in the TaAs film was improved and the TaAs phase was achieved. Our work presents an effective method for the fabrication of TaAs films using PLD, enabling possible use of the Weyl semimetal film for functional devices.