Scientists have used the tip of a scanning tunnelling microscope to manipulate electrons in graphene, potentially making the material usable for more applications:
Graphene – a one-atom-thick layer of the stuff in pencils – is a better conductor than copper and is very promising for electronic devices, but with one catch: Electrons that move through it can't be stopped.
Until now, that is. Scientists at Rutgers University-New Brunswick have learned how to tame the unruly electrons in graphene, paving the way for the ultra-fast transport of electrons with low loss of energy in novel systems. Their study was published online in Nature Nanotechnology [DOI: 10.1038/nnano.2017.181] [DX].
[...] [Eva Y. Andrei's] team managed to tame these wild electrons by sending voltage through a high-tech microscope with an extremely sharp tip, also the size of one atom. They created what resembles an optical system by sending voltage through a scanning tunneling microscope, which offers 3-D views of surfaces at the atomic scale. The microscope's sharp tip creates a force field that traps electrons in graphene or modifies their trajectories, similar to the effect a lens has on light rays. Electrons can easily be trapped and released, providing an efficient on-off switching mechanism, according to Andrei.
Related: Electrons Controlled in Graphene on a Sub-Femtosecond Scale Using Lasers
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https://www.fau.eu/2017/09/25/news/research/the-fastest-light-driven-current-source/
Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
[...] For their experiments, the scientists fired extremely short laser pulses with specially engineered waveforms onto graphene. When these light waves hit the graphene, the electrons inside were hurled in one direction, like a whiplash. 'Under intense optical fields, a current was generated within a fraction of an optical cycle – a half femtosecond. It was surprising that despite these enormous forces, quantum mechanics still plays a key role,' explains Dr. Takuya Higuchi from the Chair of Laser Physics, the first author of the publication.
Light-field-driven currents in graphene (DOI: 10.1038/nature23900) (DX)
(Score: 0) by Anonymous Coward on Wednesday October 25 2017, @06:37PM (1 child)
There have been a billion discoveries, but nothing seems to materialize in the market.
(Score: 0) by Anonymous Coward on Wednesday October 25 2017, @10:02PM
I at first misread the title as "Smart Tunneling Microscope", perhaps that is what they need to take advantage of graphene.
(Score: 0) by Anonymous Coward on Thursday October 26 2017, @01:17AM
"Sending voltage"--what a lovely misnomer! Voltage is a potential, which you can hardly send. You can't "send" 100 meters of water down to the lower lake, but you can "send" a water current of this-and-such liter per second (amount per time) from the upper to the lower lake (with the potential difference of 100 meters). You apply a potential, you measure a current, that's STM.