Ambipolar Half-Metallicity in One-Dimensional Metal-(1,2,4,5-Benzenetetramine) Coordination Polymers via Carrier Doping

A family of one-dimensional (1D) pi-d conjugated coordination polymers (CPs) with diverse magnetic properties are reported on the basis of first-principles calculations and coordinative assembly of metal (TM = Cr, Mn, Fe, Co, Ni, and Cu) and 1,2,4,5-benzenetetramine (BTA). Our calculations show that 1D TM-BTA are semiconductors, and Mn-, Fe-, and Co-BTA have ferromagnetic ground states. In particular, Mn- and Fe-BTA are bipolar magnetic semiconductors, which can be turned into half metals with controlled spin-polarization orientation via carrier doping. The long-range superexchange interaction between metal's d and BTA's pi orbitals is responsible for tunable ferromagnetism with large magnetic anisotropic energy. The Born-Oppenheimer molecular dynamic simulation demonstrates that TM-BTA retains their lattice structures at temperature of 800 K. The ambipolar half-metallicity endows TM-BTA potential applicability in nanoscale spintronics.