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Quantum oscillations in antiferromagnetic conductors

par Revaz Ramazashvili - 3 décembre 2010

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Discovered in 1930, magnetic quantum oscillations were the second (after superconductivity) experimentally found macroscopic manifestation of the quantum nature of the electron : in a magnetic field, the electron energy levels in a metal become discrete, which leads to oscillations of various quantities with varying the magnetic field.

For over fifty years now, magnetic quantum oscillations have been a direct and precise probe of the electron physics in metals. The scope of the quantum oscillation experiments has been ever expanding to new materials such as layered and chain compounds, magnetically ordered metals and superconductors.

Recently, breakthrough experiments have observed quantum oscillations in high-temperature superconductors. The experiments have detected small pockets of well-defined carriers in the "normal" state of YBCO. The small size of the observed carrier pockets points to an electron ordering of a yet unknown nature, and a number of studies suggest this may be a kind of antiferromagnetic order.

In a recently published Physical Review Letter, Revaz Ramazashvili of the LPT has shown, how magnetic quantum oscillations in an antiferromagnetic conductor with small carrier pockets may allow to determine the location of the detected carrier pocket in the Brillouin zone - a hitherto missing diagnostic opportunity. This opportunity may prove useful in materials of great interest, such as electron- and hole-doped cuprates, iron pnictides, as well as organic and heavy fermion compounds.