Nonadditive Transport in Multi‐Channel Single‐Molecule Circuits

Abstract

As stated in the classic Kirchhoff's circuit laws, the total conductance of two parallel channels in an electronic circuit is the sum of the individual conductance. However, in molecular circuits, the quantum interference (QI) between the individual channels may lead to apparent invalidity of Kirchhoff's laws. Such an effect can be very significant in single‐molecule circuits consisting of partially overlapped multiple transport channels. Herein, an investigation on how the molecular circuit conductance correlates to the individual channels is conducted in the presence of QI. It is found that the conductance of multi‐channel circuit consisting of both constructive and destructive QI is significantly smaller than the addition of individual ones due to the interference between channels. In contrast, the circuit consisting of destructive QI channels exhibits an additive transport. These investigations provide a new cognition of transport mechanism and manipulation of transport in multi‐channel molecular circuits.

Single-Molecule Junctions with Highly Improved Stability

“…scanning-tunneling microscopy break junction (STM-bj). [26][27][28][29][30][31] or mechanically controlled breakjunction (MCBJ), [32][33][34][35][36] and graphene-based SMJs have also recently appeared in the litterature. [37][38][39] In most STM-bj experiments, the conductance is continuously recorded as an atomic contact is broken in a solution of molecules, and a conductance plateau, indicating the formation of a SMJ, is observed when a molecule comes between the two electrodes during the pulling process.…”

“…Single-molecule junctions (SMJs) , are less stable and are technically more challenging. They are fabricated mainly by two techniques, i.e., scanning tunneling microscopy break junction (STM-bj) − or mechanically controlled break junction (MCBJ). − Graphene-based SMJs have also recently appeared in the literature. − In most STM-bj experiments, the conductance is continuously recorded as an atomic contact is broken in a solution of molecules, and a conductance plateau, indicating the formation of a SMJ, is observed when a molecule comes between the two electrodes during the pulling process. The Au tip is further stretched into a thin gold wire and finally breaks.…”

Grid-Based Correlation Analysis to Identify Rare Quantum Transport Behaviors

“…[7][8][9] A significant and ongoing challenge in the investigation of transport through single molecule systems, however, is extracting meaning from the large and stochastic datasets typically produced by experimental techniques such as the scanning tunneling break junction (STM-BJ) [10][11][12][13][14][15][16] and mechanically controlled break junction (MCBJ). [17][18][19][20][21][22][23][24] Both of these methods involve forming and then breaking a thin metal constriction to create a single-molecule junction in the nano-gap between two metal electrodes. The primary data collected is the conductance (G = I / V) through the junction during the breaking process as a function of how much the two sides have been pulled apart, known as a "breaking trace".…”

“…Single-molecule electronics have the potential to enable cheap and efficient circuit fabrication at the ultimate size limit and also provide an appealing test-bed for exploring intriguing physical phenomena at the nanoscale such as quantum interference, − spin filtering, , and interfacial coupling. − A significant and ongoing challenge in the investigation of transport through single-molecule systems, however, is extracting meaning from the large and stochastic data sets typically produced by experimental techniques such as the scanning tunneling microscope break junction (STM-BJ) − and mechanically controlled break junction (MCBJ). − Both of these methods involve forming and then breaking a thin metal constriction to create a single-molecule junction in the nanogap between two metal electrodes. The primary data collected is the conductance ( G = I / V ) through the junction during the breaking process as a function of how much the two sides have been pulled apart, known as a “breaking trace”.…”

Detecting Air Pollutant Molecules Using Tube-Shaped Single Electron Transistor

“…High gas-sensing abilities have been found in low-dimensional nanostructures, such as carbon nanotubes [ 11 ], ZnO nanobelts [ 12 ], silicon [ 13 ], In O [ 14 ], and SnO [ 15 ] nanowire-based sensors, and two-dimensional materials, such as graphene [ 16 ] and MoS [ 17 ]. However, those sensors are mostly based on coherent electronic transport [ 18 ]. Inevitably, electric heat will be produced during the operation of these sensors, and their large power costs will affect the high sensitivities of the sensors.…”