Two‐Dimensional Electron Gases Continue to Exhibit Intriguing Behavior

DEC 01, 1998

Researchers have taken a closer look at some funny structure noted years ago in the resistivity of a quantum Hall sample at low magnetic fields. The prevailing explanation for what they see is that the electrons are forming charge density waves.

DOI: 10.1063/1.882482

Barbara Goss Levi

The startling discoveries of the integral and fractional quantum Hall effects were made in two‐dimensional electron gases subjected to very high magnetic fields (see the story on page 17). Now, it appears, other surprises await us at lower fields. In a recent study, the longitudinal resistivity exhibited a strong anisotropy in a certain range of temperature and magnetic field: When plotted as a function of the magnetic field, the resistivity has a dip when the current flows in one direction and a strong peak when it flows in an orthogonal direction. There’s no a priori reason to think that these two directions are different.

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