New insights may be on their way from an unlikely source. Cold-atom researchers are hoping to capture the physics of high-Tc superconductors by mimicking the electrons with neutral atoms in an array of optical traps. If they succeed, they’ll be able to study the inner workings of the superconducting and related phases in a way that’s otherwise inaccessible to either theory or experiment. Trapped atoms can be interrogated and manipulated one by one. Electrons in a solid can’t.
In realizing that hope, the main challenge is temperature. Though at just tens of nanokelvin they are ultracold by any absolute standards, state-of-the-art atomic experiments act like solids with temperatures of hundreds of kelvin, far from the most enticing parts of the cuprate phase diagram. Now Harvard University’s Markus Greiner and colleagues have taken a step into uncharted territory.1 They’ve cooled their system of lithium-6 atoms far enough to see antiferromagnetic order—the checkerboard pattern in figure 1—across their entire 80-site two-dimensional lattice. “Interesting states like high-Tc superconductivity are often found in the vicinity of antiferromagnetism,” says Greiner. So although the experiments haven’t turned up any new physics just yet, it may not be long before they do.
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