  Weyl semimetals (WSMs), a new type of topological condensed matter, are
currently attracting great interest due to their unusual electronic states and
intriguing transport properties such as chiral anomaly induced negative
magnetoresistance, a semi--quantized anomalous Hall effect and the debated
chiral magnetic effect. These systems are close cousins of topological
insulators (TIs) which are known for their disorder tolerant surface states.
Similarly, WSMs exhibit unique topologically protected Fermi arcs surface
states. Here we analyze electron--phonon scattering, a primary source of
resistivity in metals at finite temperatures, as a function of the shape of the
Fermi arc where we find that the impact on surface transport is significantly
dependent on the arc curvature and disappears in the limit of a straight arc.
Next, we discuss the effect of strong surface disorder on the resistivity by
numerically simulating a tight binding model with the presence of quenched
surface vacancies using the Coherent Potential Approximation (CPA) and
Kubo--Greenwood formalism. We find that the limit of a straight arc geometry is
remarkably disorder tolerant, producing surface conductivity that is a factor
of 50 larger of a comparable set up with surface states of TI. Finally, a
simulation of the effects of surface vacancies on TaAs is presented,
illustrating the disorder tolerance of the topological surface states in a
recently discovered WSM material.
