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A Material Found To Carry Current In a Way Never Before Observed (phys.org)
An anonymous reader quotes a report from Phys.Org: Scientists at the Florida State University-headquartered National High Magnetic Field Laboratory have discovered a behavior in materials called cuprates that suggests they carry current in a way entirely different from conventional metals such as copper. The research, published today in the journal Science, adds new meaning to the materials' moniker, "strange metals." Cuprates are high-temperature superconductors (HTS), meaning they can carry current without any loss of energy at somewhat warmer temperatures than conventional, low-temperature superconductors (LTS). Although scientists understand the physics of LTS, they haven't yet cracked the nut of HTS materials. Exactly how the electrons travel through these materials remains the biggest mystery in the field.
For their research on one specific cuprate, lanthanum strontium copper oxide (LSCO), a team led by MagLab physicist Arkady Shekhter focused on its normal, metallic state -- the state from which superconductivity eventually emerges when the temperature dips low enough. This normal state of cuprates is known as a "strange" or "bad" metal, in part because the electrons don't conduct electricity particularly well. Scientists have studied conventional metals for more than a century and generally agree on how electricity travels through them. They call the units that carry charge through those metals "quasiparticles," which are essentially electrons after factoring in their environment. These quasiparticles act nearly independently of each other as they carry electric charge through a conductor. But does quasiparticle flow also explain how electric current travels in the cuprates? At the National MagLab's Pulsed Field Facility in Los Alamos, New Mexico, Shekhter and his team investigated the question. They put LSCO in a very high magnetic field, applied a current to it, then measured the resistance. The resulting data revealed that the current cannot, in fact, travel via conventional quasiparticles, as it does in copper or doped silicon. The normal metallic state of the cuprate, it appeared, was anything but normal.
For their research on one specific cuprate, lanthanum strontium copper oxide (LSCO), a team led by MagLab physicist Arkady Shekhter focused on its normal, metallic state -- the state from which superconductivity eventually emerges when the temperature dips low enough. This normal state of cuprates is known as a "strange" or "bad" metal, in part because the electrons don't conduct electricity particularly well. Scientists have studied conventional metals for more than a century and generally agree on how electricity travels through them. They call the units that carry charge through those metals "quasiparticles," which are essentially electrons after factoring in their environment. These quasiparticles act nearly independently of each other as they carry electric charge through a conductor. But does quasiparticle flow also explain how electric current travels in the cuprates? At the National MagLab's Pulsed Field Facility in Los Alamos, New Mexico, Shekhter and his team investigated the question. They put LSCO in a very high magnetic field, applied a current to it, then measured the resistance. The resulting data revealed that the current cannot, in fact, travel via conventional quasiparticles, as it does in copper or doped silicon. The normal metallic state of the cuprate, it appeared, was anything but normal.
FWIW, I read the paper and don't really think it belongs here.
It's not a working paper, but what they're describing isn't some huge new model, but rather observations, first of what's not happening, and then some measured properties about what is happening. I'm inferring that they view the entire system as behaving in a quantum manner, but it's slightly beyond my expertise, and they talk about this work being the basis for more work that needs to be done.
It looks like good science - don't get me wrong - but /. is usually about "News" and this is more of a paper for people in the field. Most good science is kinda boring. The submitter seems to have not fully understood the topic either, which doesn't help.
My God, it's Full of Source!
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