First-principles vs. semi-empirical modeling of global and local electronic transport properties of graphene nanopore-based sensors for DNA sequencing

摘要: Using first-principles quantum transport simulations, based on the nonequilibrium Green function formalism combined with density functional theory (NEGF+DFT), we examine changes in total and local electronic currents within plane of graphene nanoribbon zigzag edges (ZGNR) hosting a nanopore which are induced by inserting DNA nucleobase into pore. We find sizable change zero-bias conductance two-terminal ZGNR + device after is placed most probable position (according to molecular dynamics trajectories) inside small diameter \mbox{$D=1.2$ nm}. Although such effect decreases as size increased \mbox{$D=1.7$ nm}, contrast between systems can be enhanced applying bias voltage $V_b \lesssim 0.1$ V. This explained microscopically being due nucleobase-induced modification spatial profile current around ZGNR. repeat same analysis using NEGF self-consistent charge tight-binding (NEGF+SCC-DFTB) or extended H\"{u}ckel (NEGF+SC-EH) semi-empirical methodologies. The large discrepancy results obtained from NEGF+DFT vs. those NEGF+SCC-DFTB NEGF+SC-EH approaches could great importance when selecting proper computational algorithms for {\em silico} design optimal nanoelectronic sensors rapid sequencing.