  Weyl semimetals are gapless topological states of matter with broken
inversion and/or time reversal symmetry, which can support unconventional
responses to externally applied electrical, optical and magnetic fields. Here
we report a new photogalvanic effect in type-II WSMs, MoTe2 and Mo0.9W0.1Te2,
which are observed to support a circulating photocurrent when illuminated by
circularly polarized light at normal incidence. This effect occurs exclusively
in the inversion broken phase, where crucially we find that it is associated
with a spatially varying beam profile via a new dispersive contribution to the
circular photogalvanic effect (s-CPGE). The response functions derived for
s-CPGE reveal the microscopic mechanism of this photocurrent, which are
controlled by terms that are allowed in the absence of inversion symmetry,
along with asymmetric carrier excitation and relaxation. By evaluating this
response for a minimal model of a Weyl semimetal, we obtain the frequency
dependent scaling behavior of this form of photocurrent. These results
demonstrate opportunities for controlling photoresponse by patterning optical
fields to store, manipulate and transmit information over a wide spectral
range.
