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 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.

Broadband and wide angle nonreciprocal thermal emission from Weyl semimetal structures

“…Towards this goal, recent experiments have begun to demonstrate the feasibility of growing single WSM thin films. More specifically, tantalum-arsenide (TaAs) is the first experimentally discovered [36,37] WSM material and recent experiments have demonstrated growth of TaAs thin films via molecular beam epitaxy [38] and pulsed laser deposition [39]. Ge thin films have been deposited on metallic substrates via electron beam evaporation [40] and thin tungsten films have been grown using atomic layer deposition (ALD) [41].…”