Impact of edge shape on the functionalities of graphene-based single-molecule electronics devices

Abstract

We present an ab initio analysis of the impact of edge shape and graphene-molecule anchor coupling on the electronic and transport functionalities of graphene-based molecular electronics devices. We analyze how Fano-like resonances, spin filtering, and negative differential resistance effects may or may not arise by modifying suitably the edge shapes and the terminating groups of simple organic molecules. We show that the spin filtering effect is a consequence of the magnetic behavior of zigzag-terminated edges, which is enhanced by furnishing these with a wedge shape. The negative differential resistance effect is originated by the presence of two degenerate electronic states localized at each of the atoms coupling the molecule to graphene which are strongly affected by a bias voltage. The effect could thus be tailored by a suitable choice of the molecule and contact atoms if edge shape could be controlled with atomic precision.

A Dramatic Odd–Even Oscillating Behavior for the Current Rectification and Negative Differential Resistance in Carbon‐Chain‐Modified Donor–Acceptor Molecular Devices

“…[ 42 ] For example, the LUMO levels for group M(C 2 i + 1 ) can evolve with the V-type line. The states localized at the sides are more sensitive to bias.…”

“…The states localized at the sides are more sensitive to bias. [ 42 ] For example, the LUMO levels for group M(C 2 i + 1 ) can evolve with the V-type line. Our calculations show that these LUMO states are localized on the left carbon chains under positive bias but on the right carbon chains under negative bias since they are extremely sensitive to the direction of the external fi eld (bias).…”

Edge state effects in junctions with graphene electrodes

“…The theoretical investigation of such structures was started recently for all-carbon junctions [12][13][14][15][16][17][18][19][20] and junctions with different organic molecules. [21][22][23][24] In particular, one example is the experimental 6,7 and theoretical 6,14,[16][17][18] investigations of linear atomic carbon chains between single-layer graphene electrodes and the first experimental observation of the current through the molecular junction with few-layer electrodes. 25 The other advantage of graphene electrodes is that the molecular gating problem could be solved.…”

Nonequilibrium transport response from equilibrium transport theory

“…However, these junctions show NDR when the terminating atoms are slightly displaced away from the chains. 21 The I -V curves of the two junctions are plotted in the right panels of Fig. 1.…”