  Weyl fermion, also referred to as pseudo-magnetic monopole in momentum space,
is an undiscovered massless elementary particle with half-integer spin
predicted according to relativistic quantum field theory. Motivated by the
recent experimental observation of Weyl semimetal band in ultracold Bose gases
with Raman-assisted 3D spin-orbit coupling, we investigate the properties and
possible observation of Weyl fermions in the low-energy quasi-particle
excitations of ultracold Fermi gases. Following a previous suggestion that the
existing Raman lattice scheme can be readily generalized to fermionic systems,
here we discuss the movement of the Weyl points in the Brillouin Zone, as well
as the creation and annihilation of Weyl fermions by adjusting the effective
Zeeman field. The relevant topological properties are also demonstrated by
calculating the Chern number. Furthermore, we propose how to experimentally
verify the existence of the Weyl fermions and the associated quantum phase
transition via density profile measurements.
