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Phenomenon that fights with superconductivity universal across both flavors of cuprates

Date:
January 15, 2015
Source:
Canadian Institute for Advanced Research
Summary:
Researchers have spotted charge ordering -- a phenomenon that interferes with superconductivity -- in electron-doped copper-oxide crystals for the first time. The discovery is a critical step towards achieving zero electrical resistance at room temperature.
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h the crystal lattice of a material without resistance. In copper-oxide compounds, or cuprates, high-temperature superconductivity is achieved in crystals that have electrons either added or removed from their atoms.

When electrons are removed, the process is called hole-doping. Physicists have known for a few years that in hole-doped copper-oxides an event called charge ordering competes with superconductivity once temperatures begin to warm up from near absolute zero.

In a typical crystal, atoms form highly-organized periodic lattices and so do their electrons. But in some materials, an instability causes some electrons to reorganize, forming new periodic patterns of charge, which do not follow the underlying atoms. This is called charge ordering. In hole-doped cuprates this charge ordering disturbs the delicate pattern required for superconductivity, leading the material to fluctuate between the two states until the temperature cools enough for superconductivity to win.

"You essentially have a fight between charge ordering and superconductivity," da Silva Neto says.

The new study reveals that charge ordering also happens in electron-doped cuprates and is therefore universal across both flavours of cuprates, despite most scientific evidence to date suggesting otherwise.

What's more, past research has led scientists to believe that charge ordering only happens during a transition stage to superconductivity called the pseudogap.

"In the hole-doped cuprates, where all the experiments have been done, it all goes back to this mysterious pseudogap phase," da Silva Neto says.

Studies had so far suggested that charge ordering requires the pseudogap state in order to occur -- leading to many attempts to explain the former in terms of the later. However, this study detected charge ordering at a higher temperature than the pseudogap phase, contradicting what has become a paradigm in the field. The result suggests a new direction for understanding the problem.

"The discovery of charge ordering has been huge. It has really caused a boom in the field, giving it some new life in the last few years," da Silva Neto says. "It gives us hope that if we can tune it or manipulate it out of the system, the critical temperature for superconductivity could go higher."

The new study reveals that charge ordering behaves in ways scientists did not expect, opening new possibilities for future explorations.


Story Source:

Materials provided by Canadian Institute for Advanced Research. Note: Content may be edited for style and length.


Journal Reference:

  1. E. H. da Silva Neto, R. Comin, F. He, R. Sutarto, Y. Jiang, R. L. Greene, G. A. Sawatzky, A. Damascelli. Charge ordering in the electron-doped superconductor Nd2-xCexCuO4. Science, 2015; 347 (6219): 282 DOI: 10.1126/science.1256441

Cite This Page:

Canadian Institute for Advanced Research. "Phenomenon that fights with superconductivity universal across both flavors of cuprates." ScienceDaily. ScienceDaily, 15 January 2015. <www.sciencedaily.com/releases/2015/01/150115142233.htm>.
Canadian Institute for Advanced Research. (2015, January 15). Phenomenon that fights with superconductivity universal across both flavors of cuprates. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/01/150115142233.htm
Canadian Institute for Advanced Research. "Phenomenon that fights with superconductivity universal across both flavors of cuprates." ScienceDaily. www.sciencedaily.com/releases/2015/01/150115142233.htm (accessed May 23, 2017).

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