  AlP and GaN are wide band-gap semiconductors (SC) uses in opto-electronic
industry as light emitting diodes. Here we investigate it as future perspective
candidate for insulating barrier in magnetic tunnel junctions. We employ
density functional theory for ground state electronic properties and
non-equilibrium Green's function method for quantum transport and examined
Co/AlP/Co and Co/GaN/Co MTJs. We find that both AlP and GaN valance band maxima
are predominantly made with $p_z$-type orbitals while conduction band minima
are $s$-type symmetry. We find that both AlP and GaN filter $\Delta_1$ symmetry
of Bloch states at $\Gamma$-point and transmission coefficient at any energy
level in-between the band-gap of materials, is mostly driven by $\Delta_1$
symmetry of Bloch states tunnel via $\Gamma$-point in first Brillouin zones. We
find large magneto-resistance $\sim$300\% in Co/AlP/Co MTJs at zero-bias. In
Co/GaN/Co MTJs we find $\sim$300\% TMR at 1.25 eV below the Fermi energy
($E_{F}-1.25$)~eV, while $\sim$10\% TMR around $E_F$ in zero-bias calculations.
We notice that both majority and minority $\Delta_{2'}$ symmetry of Bloch
states with rather different $spd$-orbitals compositions tunnel in
Co[0001]/AlP[0001] MTJs and exhibit non-zero TMR, whereas in Co[111]/GaN[0001]
MTJs, the both majority and minority $\Delta_1$ symmetry of Bloch states with
different energy-gradient tunnels at Fermi energy level along [111] transport
direction. Our work accentuate the process for systematic, efficient, accurate
and versatile framework to design the semiconductors based MTJs for low power
electronics.
