Synopsis: Hall Effect in Quasi-1D Conductors

Experiments have uncovered a new form of Hall effect in organic conductors that confine current flow mostly along one-dimensional molecular strands.
Synopsis figure
K. Kobayashi et al., Phys. Rev. Lett. (2014)

Quasi-1D organic conductors are made up of an array of long molecular strands that confine the flow of electrons to essentially one dimension. This reduced dimensionality results in unique behaviors, such as angle-dependent magnetoresistance. New experiments with a particular quasi-1D organic conductor have revealed an unexpected Hall effect. As reported in Physical Review Letters, the characteristic Hall resistance oscillates as the orientation of the magnetic field is rotated with respect to the conductor’s lattice structure.

The Hall effect occurs when a magnetic field is applied perpendicular to the current flowing in a material. The magnetic force causes charge carriers to accumulate on the sides of the material, resulting in a transverse voltage. If the charge carriers are confined to two dimensions, the Hall effect becomes quantized, in that the Hall resistance (the ratio of transverse voltage to longitudinal current) takes on discrete values.

One would not expect a Hall effect in a truly one-dimensional conductor. However, Kaya Kobayashi of Aoyama Gakuin University in Kanagawa, Japan, and collaborators have discovered a Hall-like response in the quasi-1D organic conductor (TMTSF)2ClO4. They placed single crystals of this conductor in a 15-tesla magnet and measured the transverse voltage as current flowed along the molecular strands. When the team varied the angle between the magnetic field and the crystal lattice, the Hall resistance oscillated from positive to negative values, crossing zero at so-called “magic angles.” These angles correspond to lattice planes that connect a molecular strand to its nearby neighbors. To explain this novel Hall effect, the researchers assume the magnetic field excites an orbital resonance that allows electrons to skip between different strands. – Michael Schirber


Features

More Features »

Announcements

More Announcements »

Subject Areas

MagnetismMaterials Science

Previous Synopsis

Industrial Physics

Tuning Ductility

Read More »

Next Synopsis

Atomic and Molecular Physics

Giving Weight to Antimatter

Read More »

Related Articles

Synopsis: A Crystal Ball for 2D Materials
Materials Science

Synopsis: A Crystal Ball for 2D Materials

Researchers predict new two-dimensional materials whose structures differ from their three-dimensional counterparts. Read More »

Viewpoint: Electron Pulses Made Faster Than Atomic Motions
Atomic and Molecular Physics

Viewpoint: Electron Pulses Made Faster Than Atomic Motions

Electron pulses have shattered the 10-femtosecond barrier at which essentially all atomic motion is frozen in materials. Read More »

Focus: Ultrafast Switch with Organic Crystal
Condensed Matter Physics

Focus: Ultrafast Switch with Organic Crystal

An organic crystal was switched between paraelectric and ferroelectric states in a picosecond. Similar materials could eventually serve as extremely fast digital switches. Read More »

More Articles