An ab-initio study of nodal-arcs, axial strain's effect on nodal-lines & Weyl nodes and Weyl-contributed Seebeck coefficient in TaAs class of Weyl semimetals
arXiv:2403.18169
Abstract
This work verifies the existence of dispersive \textit{nodal-arcs} and their evolution into Weyl nodes under the effect of spin-orbit coupling (SOC) in NbAs & NbP. The obtained features mimic the observations as reported for TaAs & TaP in our previous work. In addition, this work reports that the number of nodes in TaAs class of Weyl semimetals (WSMs) can be altered via creating strain along or direction of the crystal. For instance, the number of nodes in NbAs under SOC-effect along with 2% (3%) tensile-strain in direction is found to be 40 (56) in its full Brillouin zone (BZ). Besides the nodes, such strain are found to have considerable impact on the nodal-lines of these WSMs when effect of SOC is ignored. A 3\% tensile (compressive) strain along the () direction leads to the partially merging of nodal-lines (without SOC) in the extended BZ of NbAs \& NbP, which is not observed in TaAs & TaP within the range of -3% to 3% strain. Apart from this, the work discusses the role of Weyl physics in affecting the Seebeck coefficient () of any WSM. In this direction, it is discussed that how a symmetric Weyl cone, even if tilted, will have no contribution to the of WSMs. Furthermore, the work highlights the conditions under which a Weyl cone can contribute to the of a given WSM. Lastly, the discussion of Weyl contribution to is validated over TaAs class of WSMs via investigating the features of their Weyl cones and calculating the contributions of such cones to the of these semimetals. The value of contributed from Weyl cone is found to be as large as 65 \textit{V}/\textit{K} below 25 K in case of TaAs. The findings of this work present a possibility of engineering the topological properties of TaAs class of WSMs via creating strain in their crystal. It also makes the picture of Weyl physics impact on the of WSMs a more clear.