Atomic chains of group-IV elements and III-V and II-VI binary compounds studied by a first-principles pseudopotential method

Using the first-principles plane wave pseudopotential method we have studied structural, electronic, and transport properties of atomic chains of group-IV elements and group III-V and group II-VI binary compounds. Several materials which are insulating or semiconducting in bulk are found to be metallic in nanowire structures. Our calculations reveal that monatomic chains of Si, Ge, and Sn elements, and of binary compounds such as InP, GaAs, and AlSb, are stable and metallic. On the other hand, compound wires of BN, SiC, GaN, ZnSe, and several others have semiconducting or insulating properties. Ideal mechanical strength calculations show that some of these atomic chains can sustain strains of up to epsilon=0.3. We have presented ab initio electron transport calculations for Si and AlP linear chain segments in between Al electrodes. Conductance of Si monatomic chains displays some nontrivial features as the number of atoms in the chain is varied or as the chain is strained. In addition to single atomic chain structures, junctions and grid structures of Si are investigated.