First-principles calculations of conductance within a plane wave basis set via non-orthogonal Wannier-type atomic orbitals

Li, Zhenyu;Kosov, Daniel

Abstract

We present a plane-wave/pseudopotential implementation of a method to calculate the electron transport properties of nanostructures. The conductance is calculated via the Landauer formula within the formalism of Green's functions. Non-orthogonal Wannier-type atomic orbitals are obtained by sequential unitary rotations of virtual and occupied Kohn–Sham orbitals, followed by two-step variational localization. We use these non-orthogonal Wannier-type atomic orbitals to partition the Kohn–Sham Hamiltonian into electrode–contact–electrode submatrices. The electrode parts of the system are modelled by two metal clusters with additional Lorentzian broadening of discrete energy levels. We examined our implementation by modelling the transport properties of Na atomic wires. Our results indicate that with the appropriate level broadening the small cluster model for contacts reproduces odd–even oscillations of the conductance as a function of the nanowire length.

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1361-648X

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Institute of Physics Publishing

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10.1088/0953-8984/18/4/019