Amazing stuff! Will this be just a scientific curiosity or ...
"... Unlike in typical materials, where energy particles scatter upon meeting phonons, in Re6Se8Cl2, they bind together. This union forms unique quasiparticles, known as acoustic exciton-polarons. These aren’t just your everyday particles; they can move without scattering, potentially heralding faster and more efficient devices.
Not only did the quasiparticles zip through Re6Se8Cl2 at speeds double that of electrons in silicon, but they also covered vast distances. And instead of electricity, these quasiparticles were controlled by light, which means that devices based on this setup could theoretically cycle at the femtosecond scale — six orders of magnitude faster than the nanosecond achievable in current Gigahertz chips. All of this is achievable at room temperature ..."
"... Rather than scattering when they come into contact with phonons, excitons in Re6Se8Cl2 actually bind with phonons to create new quasiparticles called acoustic exciton-polarons. Although polarons are found in many materials, those in Re6Se8Cl2 have a special property: they are capable of ballistic, or scatter-free, flow. This ballistic behavior could mean faster and more efficient devices one day. ...
“In terms of energy transport, Re6Se8Cl2 is the best semiconductor that we know of, at least so far,” ...
Superatoms are clusters of atoms bound together that behave like one big atom, but with different properties than the elements used to build them. ..."
Superatoms are clusters of atoms bound together that behave like one big atom, but with different properties than the elements used to build them. ..."
From the editor's summary and abstract:
"Editor’s summary
Energy carriers inside materials encounter resistance from sources such as impurities and lattice vibrations. Extending the mean free path, the distance between the collisions that the carriers experience, is important for applications. ... achieved this goal in the van der Waals semiconductor Re6Se8Cl2. The researchers used light to create excitons (pairs of holes and electrons) and then imaged their transport. The particles propagated quasiballistically over several micrometers at room temperature. This unusually robust transport could be attributed to the binding of excitons to an acoustic lattice deformation. ...
Abstract
The transport of energy and information in semiconductors is limited by scattering between electronic carriers and lattice phonons, resulting in diffusive and lossy transport that curtails all semiconductor technologies. Using Re6Se8Cl2, a van der Waals (vdW) superatomic semiconductor, we demonstrate the formation of acoustic exciton-polarons, an electronic quasiparticle shielded from phonon scattering. We directly imaged polaron transport in Re6Se8Cl2 at room temperature, revealing quasi-ballistic, wavelike propagation sustained for a nanosecond and several micrometers. Shielded polaron transport leads to electronic energy propagation lengths orders of magnitude greater than in other vdW semiconductors, exceeding even silicon over a nanosecond. We propose that, counterintuitively, quasi-flat electronic bands and strong exciton–acoustic phonon coupling are together responsible for the transport properties of Re6Se8Cl2, establishing a path to ballistic room-temperature semiconductors."
A Superatomic Semiconductor Sets a Speed Record Columbia chemists discover ballistic flow in a quantum material. The finding could help overcome shortcomings in semiconductors.
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