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

TL;DR

This study explores the growth conditions of TaAs Weyl semimetal thin films using pulsed laser deposition, addressing challenges in stoichiometry and demonstrating a method to produce high-quality films for potential device applications.

Contribution

It introduces a novel approach to grow high-quality TaAs films by controlling substrate interactions and As content during pulsed laser deposition.

Findings

Partial As diffusion from GaAs substrates improves film composition.

Successful fabrication of phase-pure TaAs films.

Potential for TaAs films in functional device applications.

Abstract

TaAs, the first experimentally discovered Weyl semimetal material, has attracted a lot of attention due to its high carrier mobility, high anisotropy, nonmagnetic and strong interaction with light. These make it an ideal candidate for the study of Weyl fermions and the 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, the TaAs films were attempted to grow on different substrates using targets with different As stoichiometric ratios by pulsed laser deposition (PLD). In this work, we have found that partial As ions of the GaAs substrate are likely to diffuse into the TaAs films during growth, which was preliminarily confirmed by the structural characterization, surface topography and composition analysis. As a result, the As content in the TaAs film is improved and the TaAs phase is achieved. Our work presents an effective method to fabricate the TaAs films by PLD, providing the possible use of the Weyl semimetal film for functional devices.