Tag: materials
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Rapid cooling of semiconductors using lasers (but no sharks)
Laser cooling (also known as optical cooling) is a well-established technique…but mostly for gases. The basic idea is to disperse the thermal energy of the atoms through shining light on them: the frequency of the laser is set to be slightly lower than the energy of transition between two configurations in the atoms, so that…
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Turning graphene into an AC/DC quantum ratchet
Just as a ratchet allows rotation in one direction but not the other, quantum ratchets break the symmetry of a microscopic system to facilitate preferential motion in one direction or another. Graphene is a two-dimensional hexagonal lattice of carbon atoms. As such, it’s highly symmetrical, but beneath that lurks a potentially exploitable hidden asymmetry. If…
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In Soviet Russia, material compresses *you*
Most solids compress when squeezed, though the effect isn’t very large for most technologically important materials (metals, ceramics, and so forth). A few rare materials exhibit negative compressibility: they expand in the direction the force is exerted, though again the effect is small. However, researchers figured out a way to produce extraordinarily large negative compressibility,…
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Pore, pore, pitiful solar cells
There’s just one word for the ‘teens: plastics photovoltaics. A new experiment may have solved a problem in nanostructured silicon solar cells: a type of photovoltaic cell that uses pores to increase the effective surface area for collection of light. By separating the contribution by surface and interior recombination effects, the NREL study found that…
Bowler Hat Science 