  We introduce an operational definition of the Berry Phase Rectification
Tensor as the second-order change of polarization of a material in response to
an ideal short pulse of an electric field. Under time-reversal symmetry this
tensor depends exclusively on the Berry phases of the Bloch bands and not their
energy dispersions, making it an intrinsic property to each material which
contains contributions from both the inter-band shift currents and the
intra-band Berry Curvature Dipole. We also introduce the Solar Rectification
Vector as a technologically relevant figure of merit for a bulk photo-current
generation under ideal black-body radiation in analogy with the classic solar
cell model of Shockley and Queisser. We perform first-principles calculations
of the Berry Phase Rectification Tensor and the Solar Rectification Vector for
the Weyl semimetal TaAs and the insulator LiAsSe2 which features large shift
currents close to the peak of solar radiation intensity.
