Dear Abhinav Nag,

I will try to explain the difference between the topological Weyl and Dirac semimetals which should help to identify these two classes while neglecting the third type of topological metal, namely "Nodal-line semimetal". Before beginning with the discussion, it is important to emphasize that more informations about the crystal structure are required such as inversion-symmetry or magnetic configuration (e.g. ferromagnetic ordering in order to break the time-reversal symmetry) of the system.

In the naive band structure picture, one needs to perform DFT calculations and DFT+SOC (spin-orbit coupling) calculations. In a Weyl semimetal, including SOC, the valence and conduction bands should touch each other at isolated points around which the band structure forms non-degenerate 3D Dirac cones (at generic points in the k-space, not necessarily on high-symmetry points). The apex of this 3D Dirac cone is called a Weyl node. The crucial ingredient for the realization of a "Weyl semimetal" is the presence of SOC and either time-eversal symmetry or inversion-symmetry must be broken. In contrast, when both time-reversal symmetry and inversion-symmetry are preserved, the system exhibits a Dirac cone with a Kramers double degeneracy and therefore it is called a Dirac semimetal. By the way, each Weyl node shows fascinating physics (accompanied by the appearance of a Fermi arc) and can be related with a number +/- 1, namely a monopole charge for the Berry curvature. Some theoretically predicted Wely semimetals are e.g. pyrochlore iridates or transition-metal dichalcogenides.

Hope this helps!

Let's complete the answer by Okan. Everything is fine but,

"the band structure forms non-degenerate 3D Dirac cones"

we must add that one of the crucial ingredients is that for Weyl, cones do not have a circular crosssection, there is a strong anisotropy and cone can be tilted. Thus yuo expect different Fermi velocities along different symmetry directions.

How to identify these materials by electrical and Magnetotransport measurements?

Any suggestions?

Thanks Okan Köksal sir and Gerardo G. Naumis sir for your valuable reply to make me understand the difference between Weyl Nad Dirac semimetal.

Anoop Mampazhasseri Divakaran, Here is a fairly comprehensive review article on the transport properties of these materials that may help in their identification. https://arxiv.org/ftp/arxiv/papers/1904/1904.04454.pdf

Quantum oscillations that can be observed in the magneto-resistance and magnetization seem to provide the clearest characterization, however they are not always easy to observe and analyze.