Semi-Dirac and Weyl fermions in transition metal oxides

We show that a class of compounds with $I$4/$mcm$ crystalline symmetry hosts three-dimensional semi-Dirac fermions. Unlike the known two-dimensional points, degeneracy these points is not lifted by spin-orbit coupling due to protection nonsymmorphic -- screw rotation in $a-b$ plane and translation along $c$ axis. This found tetragonal perovskite oxides, realizable thin films epitaxial strain results a$^0$a$^0$c$^-$-type octahedral rotation. Interestingly, broken time-reversal symmetry, two pairs Weyl emerge from within Brillouin zone, an additional lattice distortion leads enhanced intrinsic anomalous Hall effect. The ability tune Berry phase can be useful novel oxide-based electronic devices.