Ab-initio quantum transport with a basis of unit-cell restricted Bloch functions and the NEGF formalism

This invited contribution illustrates the theory and application of a first-principle transport methodology employing a basis set obtained directly from the Bloch functions computed with a plane wave (PW) ab-initio solver. We start from a PW density functional theory (DFT) Hamiltonian, use a unitary transformation to real space in the transport direction, and then discuss a basis of Bloch functions enabling a huge reduction of the size of the Hamiltonian blocks and an effective suppression of possible unphysical states. Our methodology enables ab-initio transport simulations with a good computational efficiency, and we here present results for self-consistent simulations of a singlegate monolayer PtSe2 field effect transistor.