Electronic stripes and transport properties in borophene heterostructures

Abstract

We performed a theoretical investigation of the structural and electronic properties of (i) pristine and (ii) superlattice structures of borophene. In (i), by combining first-principles calculations, based on the density functional theory (DFT), and simulations of the X-ray Absorption Near-Edge Structure (XANES) spectra we present a comprehensive picture connecting the atomic arrangement of borophene and the X-ray absorption spectra. Once we characterized the electronic properties of the pristine systems, we next examined the electronic confinement effects in 2D borophene superlattices (BSLs) [(ii)]. Here, the BSL structures were made by attaching laterally two different structural phases of borophene. The energetic stability and the electronic properties of these BSLs were examined based on total energy DFT calculations. We find a highly anisotropic electronic structure, characterized by the electronic confinement effects, giving rise to “electronic stripes”, and metallic channels ruled by the superlattices. Combining DFT and the Landauer–Büttiker formalism, we investigated the electronic transport properties in BSLs. Our results of the transmission probability reveal that the electronic transport is ruled by π or a combination of π and σ transmission channels, depending on the atomic arrangement and periodicity of the superlattices. Finally, we show that there is a huge magnification of the directional dependence of the electronic transport properties in BSLs, in comparison with the pristine borophene phase. These findings indicate that BSLs are quite interesting systems in order to design conductive nanoribbons on a 2D platform.