Brookhaven National Laboratory - 02 June 2010
Glimpse of heavy electrons reveals “hidden order”Findings reveal characteristics of “hidden order” in unusual uranium compound and demonstrate new method for investigating long-standing physics problems
Using a microscope designed to image the arrangement and interactions of electrons in crystals, scientists have captured the first images of electrons that appear to take on extraordinary mass under certain extreme conditions. The technique reveals the origin of an unusual electronic phase transition in one particular material, and opens the door to further explorations of the properties and functions of so-called heavy fermions.
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Understanding heavy fermion behavior could lead to the design of new materials for high-temperature superconductors. Superconductivity allows materials to carry current with no energy loss.
Los Alamos National Laboratory - 03 June 2010
Hidden order in a Kondo latticeResearchers unravel 25-year-old physics mystery
Unconventional use of a well-known scientific instrument has helped scientists from Los Alamos National Laboratory, Brookhaven National Laboratory, and other institutions unravel a 25-year-old physics mystery and reveal a “hidden order” of the electronic structure inside an unusual superconducting material.
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The research could lead to engineered materials that exhibit superconductivity by helping physicists better understand the behavior of heavy fermion materials—exotic compounds whose slow-moving electrons behave as if they have a mass 1,000 times greater than ordinary free electrons.
Nature 465 - 03 June 2010
Condensed-matter physics: The emergent and hidden unveiledA long-standing mystery in condensed matter physics is that of the appearance of a 'hidden order' state in URu2Si2 at low temperature, an unexpected phase change that is accompanied by a sharp change in bulk properties of the material. The problem is related to the appearance of a 'heavy fermion' state (already at a higher temperature) where electron-like charge carriers propagate through the solid with an effective mass thousands of times larger than that of a free electron. Schmidt et al. have now used scanning tunnelling microscopy and spectroscopy to visualize the electronic structure of URu2Si2 with subatomic resolution. In the process, they observe the electronic structure associated with a magnetic 'Kondo' lattice, which was assumed to cause heavy fermion effects, but never observed directly. Further, the spectroscopic findings show how the hidden order state evolves with decreasing temperature from this lattice.
- Nature 465, 553-554 (03 June 2010) | doi: 10.1038/465553a
- Nature 465, 570-576 (03 June 2010) | doi: 10.1038/nature09073