Synopsis: Tuning conductance

A single-molecule junction on a silver surface exhibits orders-of-magnitude variation in conductance.
Synopsis figure
Illustration: W. F. Wang et al., Phys. Rev. Lett. (2010)

Electron transport through molecules has implications for a range of subjects. In particular, conductance through single-molecule junctions is known to have a complex dependence on atomic structure, orientation, and bonding properties. However, investigations with atomic-scale control of the junction geometry are scarce.

In their paper in Physical Review Letters, Yongfeng Wang and collaborators from Germany, Denmark, and Sweden demonstrate that the conductance in a single-molecule junction varies over orders of magnitude.

Wang et al. present scanning tunneling microscopy measurements of the conductance of tin-phthalocyanine (SnPc) adsorbed on a Ag(111) surface in contact with a tungsten tip covered with silver. By manipulating the chemical bonding between SnPc and Ag(111) through selective dehydrogenation of SnPc and an atomic-scale structuring of the electrode, the conductance of single-molecule junctions is varied from 0.013 to 0.32 in units of the quantum of conductance. The authors also perform ab initio calculations combined with a nonequilibrium Green’s function technique for a quantitative analysis of the electron transport through Ag-SnPc-Ag junctions. This opens an avenue to study current flow through single molecules by combining transport measurements with atomic manipulation capabilities of the scanning tunneling microscope. – Sarma Kancharla


Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsNanophysics

Previous Synopsis

Nuclear Physics

Exclusive pions

Read More »

Next Synopsis

Related Articles

Synopsis: Losing Light in a BEC
Atomic and Molecular Physics

Synopsis: Losing Light in a BEC

The index of refraction in a gas of bosons is enhanced relative to its value in a classical gas, a predicted quantum effect that has now been observed in ultracold sodium atoms. Read More »

Focus: Atoms As Thermometers
Atomic and Molecular Physics

Focus: Atoms As Thermometers

A small number of atoms in repeated trials can accurately measure the temperature of an ultracold gas cloud—a step toward measuring temperature on the micrometer scale. Read More »

Synopsis: Bad Cavities for Precise Lasers
Optics

Synopsis: Bad Cavities for Precise Lasers

The frequency of a laser based on trapped ultracold atoms can be made insensitive to fluctuations in the laser cavity’s length. Read More »

More Articles