  Based on recently synthesized Ni3C12S12 class 2D metal-organic frameworks, we
predict electronic properties of M3C12S12 and M3C12O12, where M is Zn, Cd, Hg,
Be, or Mg with no M orbital contributions to bands near Fermi level. For
M3C12S12, their band structures exhibit double Dirac cones with different Fermi
velocities that are n and p type, respectively, which are switchable by
few-percent strain. The crossing of two cones are symmetry-protected to be
non-hybridizing, leading to two independent channels in 2D node-line semimetals
at the same k-point akin to spin-channels in spintronics, rendering conetronics
device possible. The node line rings right at their crossing, which are both
electron and hole pockets at the Fermi level, can give rise to
magnetoresistance that will not saturate when the magnetic field is infinitely
large, due to perfect n-p compensation. For M3C12O12, together with conjugated
metal-tricatecholate polymers M3(HHTP)2, the spin-polarized slow Dirac cone
center is pinned precisely at the Fermi level, making the systems conducting in
only one spin or cone channel. Quantum anomalous Hall effect can arise in MOFs
with non-negligible spin-orbit coupling like Cu3C12O12. Compounds of M3C12S12
and M3C12O12 with different M, can be used to build spintronic and
cone-selecting heterostructure devices, tunable by strain or electrostatic
gating.
