First-principles predictions on charge mobility and half-metallicity in two dimensional metal coordination polyporphyrin sheets

We have investigated the electronic structures and carrier mobility of two dimensional (2D) metal coordination polyporphyrin (PP) sheets using density functional theory combined with Boltzmann transport method with relaxation time approximation. Two families of metal coordination atoms are studied: 1) 3d-transition metals (TM) Fe and Co; and 2) nonferrous metals (NM) Li and Zn. It is shown that 2H-PP, 2Li-PP and Zn-PP are direct gap semiconductors, while Fe-PP and Co-PP are spin-splitting and behave like half-metallic. Moreover, the charge mobilities have been carried out under periodic boundary conditions for infinite 2D PP systems, and found that the electron mobility is higher than that of the hole's, which indicating the n-type semiconducting characteristic. Furthermore, we also found the hole mobility in all systems show anisotropy in-plane. (C) 2017 Elsevier B.V. All rights reserved.