During the last years there has been a substantial development in our understanding of tiny single molecule quantum systems. It turns out that the space, "nothing", embedding the system has a profound impact on the electrical characteristics of the system. By applying a microscopic layer of tetrahydrofuran (THF) fluid the embedding space can be electrically shielded from the system. The aim of this site is to provide insight in the fundamentals of these systems for everyone interested in this fascinating micro-world where new physics and quantum effects will be revealed.
Further reading:
A quantum effect at ambient conditions is presented. A benzene dithiol (BDT) molecule or a tetrahydrofuran (THF) molecule is used as a barrier molecule bridging the gold electrodes from a Mechanically Controllable Break junction. It has been known for a long time that the environment of a junction couples to the conduction. With a microscopic layer of fluid it is actually possible to influence this coupling. The electrode-molecule-electrode configuration is lined with a microscopic layer of THF fluid, also known as the “partially wet phase”. This is effectively decoupling the electrode-molecule-electrode system from environmental modes outside of this system. The effects on coherence and quantum interference are exceptional.
An impression of a single molecule junction in the partially wet phase, not to scale. The blue/purple layer represents the THF partially wet phase layer. The red liner represents the finite width of the surface potential, trapping charge carriers at the THF/air interface. Thus, creating a miniature Faraday cage shielding the environment from the molecular system.
Decoupling environmental modes enabling one dimensional conduction:
Schematic representation of a: a single junction, b: a double junction, c: a single junction in the partially wet phase, d: a double junction in the partially wet phase.
A schematic simplified representation of the junctions under study. The single molecule is connected to two quantum wires enabling true one dimensional conduction.