First-principles treatments of electron transport properties for nanoscale junctions

First-principles transport calculation method based on real-space finite-difference nonequilibrium Green's function scheme

“…6 and Appendix A of Ref. 16. The Green's function matrix involves the inversion of an infinite matrix corresponding to the Hamiltonian matrix of the whole systemĤ (k ), where k is the lateral Bloch vector.…”

“…Thus, we can not use the two procedures mentioned above. [23][24][25] We introduce a computational procedure for obtaining N -dimensional matrices of the surface Green's functions and self-energy terms using ratio matrices in the OBM method, 16 which are computed by solving the generalized eigenvalue problem for the periodic bulk model shown in Fig. 3:…”

“…In addition, the scattering wave functions provide a direct realspace picture of the scattering process. This approach has been employed by combining it with techniques where real-space grids and/or plane-wave basis sets 8,[11][12][13][14][15][16] are used to describe wave functions and potentials. The easiest way to obtain scattering wave functions is to solve the Lippman-Schwinger equation where the semi-infinite electrode is replaced with a uniformly distributed charge background, i.e., "jellium."…”

“…11 The scattering wave function can alternatively be calculated by the wave-function-matching approach proposed by Fujimoto and Hirose, i.e., the overbridging boundary-matching (OBM) method. 8,16 In the OBM method, several parts of Green's functions of the transition region are computed to set up the wave-function-matching formula and there is no limitation of the usage of jellium, i.e., more realistic atomic and electronic structures of the electrode can be taken into account. Moreover, the effect of electrodes is included in the matching formula as N x × N y × N f -dimensional ratio matrices, where N f is the order of the finite-difference approximation 6 for the kinetic energy operator in the Kohn-Sham equation and is much smaller than N z .…”

Formation and Physical Properties of h-BN Atomic Layers: A First-Principles Density-Functional Study

“…The electronic transport properties of the h-BN atomic layers can be changed from insulating to conductive properties when C atoms are doped, suggesting a possibility to fabricate the novel opto/nanoelectronics applications [31,32,[34][35][36]40]. Furthermore, when the C atom is doped, the exotic conduction channel in h-BN monolayers would emerge, which might improve electronic transport properties [41][42][43][44][45][46]. Thus, h-BN atomic layers are promising materials to be used in nanoelectronics and optoelectronics applications.…”