Give double-layer graphene a twist and it superconducts

LOS ANGELES — Give a graphene layer cake a twist and it superconducts — electrons flow freely through it without resistance. Made up of two layers of graphene, a form of carbon arranged in single-atom-thick sheets, the structure’s weird behavior suggests it may provide a fruitful playground for testing how certain unusual types of superconductors work, physicist Pablo Jarillo-Herrero of MIT reported March 7 at a meeting of the American Physical Society.

The discovery, also detailed in two papers published online in Nature on March 5, could aid the search for a superconductor that functions at room temperature, instead of the chilly conditions required by all known superconductors. If found, such a substance could replace standard conductors in various electronics, promising massive energy savings.

Source: Give double-layer graphene a twist and it superconducts

Although this is an interesting finding, the next statement (in bold) seems a bit more relevant and exciting.

Layered graphene’s superconductivity occurs when the second layer of graphene is twisted relative to the first, at a “magic angle” of about 1.1 degrees, and when cooled below 1.7 kelvins (about –271° Celsius). Surprisingly, Jarillo-Herrero and colleagues report, the same material can also be nudged into becoming an insulator — in which electrons are stuck in place — by using an electric field to remove electrons from the material. That close relationship with an insulator is a characteristic shared by certain types of high-temperature superconductors, which function at significantly warmer temperatures than other superconductors, although they still require cooling.

Anyone else see the possibility for a relatively medium temperature superconducting transistor that has the ability to switch rapidly? If they can "productize" the twisting on a micro-scale, then it could lead to a superconducting integrated circuit design. And, i the research does find a way to increase the temps to standard room temperature, then the potential for a room temperature superconducting CPU & RAM memory would be theoretically possible.

Interesting research to follow for the next 5-10 years for sure.

I'm sitting in my electronics fundamentals class right now drooling a little bit.

a reply to: Krakatoa


Room temp superconductor is awesome.

It will change everything.

a reply to: burgerbuddy

Yes it will.

In ways most people don't understand yet.

We're so used to waiting for things to charge. Those days will be over sooner rather than later.

If we could charge electric vehicles with this technology, "supercharging" your Tesla will take a minute or less, which would instantly make the act of charging your car no more of a hassle than pumping gas.

Every excuse not to switch to electric is fading from view.

I wish they'd stop making things and start making things.

but room temp superconductors breaks the old rule of them being unfeasable due to the super cooled environment in which they exhibit their super properties.

I want a flying car now... hurry up.

Eh using the casimir effect with lead and gold does the trick...

One has to think of atomic weight/halflifes etc. when looking for such things, see super cooling is sort of the same as super heating at a certain temperature; there is a point in materials/elements called flashpoint there is also a point similar or freeze point. Taking two similar like that of lead and gold one particle decay exchange away from each other... and well mission accomplished rather easily as they can convert back and forth in polarity of bonds so from lead to gold and gold to lead back and forth back and forth.

Of course; casimir is the easiest of conflagration; to manipulate these two elements together in order to perform work.

The lead best works molten as it 'slags' off so of course to eliminate that a vacuum is suggested.

There's other sorts such as mercury encased in silver, over time the two will produce a unique salt.
Many metals have a crystaline structure like titanium... str0onger than steel and lighter than aluminum.

The thing about graphite is it's atoms automatically layer like a lubricant... gold and lead do the same thing, mercury shatters into smaller and smaller balls down to the atomic scale... so it can perfom better than graphine; however it has toxicity issues, but what doesn't at high concentraitions?

Anyways, have fun exploring such things.

Interestingly, if I'm understanding this correctly, Hemp is also showing some promise in the field;


Hemp Waste Fibers Form Basis of Supercapacitor More Conductive Than Graphene

Comprised of a lone hexagonal honeycomb lattice layer of tightly packed carbon atoms, graphene is one of the strongest, lightest, and most conductive compounds ever discovered. Bottom line, it’s an extraordinary composite.

However, a scientist from New York’s Clarkson University says he’s found a way to manufacture hemp waste into a material “better than graphene.” Moreover, the scientist — known to his peers as Dr. David Mitlin — says creating this graphene-like hemp material costs but a minuscule fraction of what it takes to produce graphene.

Paper by Dr. David Mitlin: Interconnected Carbon Nanosheets Derived From Hemp for Ultrafast Supercapacitors with High Energy (abstract)

[...] By taking advantage of the complex multilayered structure of a hemp bast fiber precursor, such exquisite carbons were able to be achieved by simple hydrothermal carbonization combined with activation. This novel precursor-synthesis route presents a great potential for facile large-scale production of high-performance carbons for a variety of diverse applications including energy storage.

Could Hemp Nanosheets Topple Graphene for Making the Ideal Supercapacitor?

[...] Mitlin’s team built their supercapacitors using the hemp-derived carbons as electrodes and an ionic liquid as the electrolyte. Fully assembled, the devices performed far better than commercial supercapacitors in both energy density and the range of temperatures over which they can work. The hemp-based devices yielded energy densities as high as 12 Watt-hours per kilogram, two to three times higher than commercial counterparts. They also operate over an impressive temperature range, from freezing to more than 200 degrees Fahrenheit.

originally posted by: burgerbuddy
a reply to: Krakatoa


Room temp superconductor is awesome.

It will change everything.

I've been waiting on this Technology since watching Terminator 2 in theaters. The scene where she tries to kill Dyson an ends up explaining stuff to him.

originally posted by: Krakatoa

LOS ANGELES — Give a graphene layer cake a twist and it superconducts — electrons flow freely through it without resistance. Made up of two layers of graphene, a form of carbon arranged in single-atom-thick sheets, the structure’s weird behavior suggests it may provide a fruitful playground for testing how certain unusual types of superconductors work, physicist Pablo Jarillo-Herrero of MIT reported March 7 at a meeting of the American Physical Society.

The discovery, also detailed in two papers published online in Nature on March 5, could aid the search for a superconductor that functions at room temperature, instead of the chilly conditions required by all known superconductors. If found, such a substance could replace standard conductors in various electronics, promising massive energy savings.

Source: Give double-layer graphene a twist and it superconducts

Although this is an interesting finding, the next statement (in bold) seems a bit more relevant and exciting.

Layered graphene’s superconductivity occurs when the second layer of graphene is twisted relative to the first, at a “magic angle” of about 1.1 degrees, and when cooled below 1.7 kelvins (about –271° Celsius). Surprisingly, Jarillo-Herrero and colleagues report, the same material can also be nudged into becoming an insulator — in which electrons are stuck in place — by using an electric field to remove electrons from the material. That close relationship with an insulator is a characteristic shared by certain types of high-temperature superconductors, which function at significantly warmer temperatures than other superconductors, although they still require cooling.

Anyone else see the possibility for a relatively medium temperature superconducting transistor that has the ability to switch rapidly? If they can "productize" the twisting on a micro-scale, then it could lead to a superconducting integrated circuit design. And, i the research does find a way to increase the temps to standard room temperature, then the potential for a room temperature superconducting CPU & RAM memory would be theoretically possible.

Interesting research to follow for the next 5-10 years for sure.

If they can integrate that with existing silicon manufacturing techniques, that will be a winner. This happened with MEMS sensors (Micro Electro-Mechanical Sensors). They could etch out mechanical components like gyroscopes, gravitometers, magnetometers, chemical and biological sensors, and digital mirrors all at a micro-chip size.They are getting close to getting quantum computers done this way. If they can make one pair of quantum computing bits, they can make a whole array.

If it weren't for the need for all that absolute zero cooling, MRI scanners would be as thin as a hula-hoop. For CPU's, just by having superconducting materials, that would eliminate the problem of overheating when overclocking.

Those are the smartest lines I thing Arnold ever had to say!
good catch


a reply to: Arnie123

a reply to: Krakatoa

What is your definition of a "relatively medium temperature"?

Below 1.7 Kelvin?

a reply to: BEBOG

So that’s what the alchemists of old were doing with there turning lead into gold thing?

The angle is very specific. And they never said if it was room temperature or not. That is why I never posted in the Graphene MEGA thread. It is the details that matter when it comes to stories like this.

Graphene already superconducts at 4 K. They think C60 (Buckyballs) can encase an element and both combined will be a room temperature superconductor. Last year, NextBigFuture ran a story about some story for a room temperature superconductor found in Japan. That is the only place I ever found that story.

The big announcement is (phys.org) Method to grow large single-crystal graphene could advance scalable 2-D materials.

If they can do something crazy like make double walled graphene nanotubes at that specific 1.3 degree angle difference, then you would be talking the talk. Until then, like all other graphene announcements, nice to see progress but until I hold that graphene battery in my grubby little hands... meh.

S+F because science is cool!

originally posted by: badw0lf
I wish they'd stop making things and start making things.

but room temp superconductors breaks the old rule of them being unfeasable due to the super cooled environment in which they exhibit their super properties.

What rule is that? I don't know of any rule against it, just that none have ever been observed, but if we keep experimenting with different materials, who knows what we might find?

originally posted by: Krakatoa
Anyone else see the possibility for a relatively medium temperature superconducting transistor that has the ability to switch rapidly?

I don't know how you made the leap to relatively medium temperature on this graphene topic, because as far as I know the temperature for this effect is very low.

There are other more promising materials for "relatively medium temperature" superconductors as you put it, as described in this article:

Superconductivity record sparks wave of follow-up physics

If Eremets and colleagues are right, then other hydrogen compounds may be good candidates for high-temperature superconductivity too. For instance, other researchers have published theory papers on arXiv suggesting compounds that pair hydrogen with platinum, potassium, selenium or tellurium, instead of sulfur.

Taking a slightly different tack, Zhang in Dallas and Yugui Yao of the Beijing Institute of Technology in China predict that substituting 7.5% of the sulfur atoms in hydrogen sulfide with phosphorus and upping the pressure to 2.5 million atmospheres (250 GPa) could raise the superconducting transition temperature all the way to 280 K6, which is above water's freezing point.

I'm not holding my breath for room temperature graphene superconductors since there seem to be more promising alternative materials for that, but it's still some interesting research at very low temperatures.

originally posted by: Arbitrageur

originally posted by: badw0lf
I wish they'd stop making things and start making things.

but room temp superconductors breaks the old rule of them being unfeasable due to the super cooled environment in which they exhibit their super properties.

What rule is that? I don't know of any rule against it, just that none have ever been observed, but if we keep experimenting with different materials, who knows what we might find?

originally posted by: Krakatoa
Anyone else see the possibility for a relatively medium temperature superconducting transistor that has the ability to switch rapidly?

I don't know how you made the leap to relatively medium temperature on this graphene topic, because as far as I know the temperature for this effect is very low.

There are other more promising materials for "relatively medium temperature" superconductors as you put it, as described in this article:

Superconductivity record sparks wave of follow-up physics

If Eremets and colleagues are right, then other hydrogen compounds may be good candidates for high-temperature superconductivity too. For instance, other researchers have published theory papers on arXiv suggesting compounds that pair hydrogen with platinum, potassium, selenium or tellurium, instead of sulfur.

Taking a slightly different tack, Zhang in Dallas and Yugui Yao of the Beijing Institute of Technology in China predict that substituting 7.5% of the sulfur atoms in hydrogen sulfide with phosphorus and upping the pressure to 2.5 million atmospheres (250 GPa) could raise the superconducting transition temperature all the way to 280 K6, which is above water's freezing point.

I'm not holding my breath for room temperature graphene superconductors since there seem to be more promising alternative materials for that, but it's still some interesting research at very low temperatures.

The "leap" as you all it is an observation that if this research continues over the next 5-10 years the possibility exists to raise the temp (if you read my entire post, you would have seen that). As for other materials, many of the higher temp superconductors do not exhibit the dual property of being switchable from super conductor to insulator like this material. That is one of the differentiating factors IMO. That makes it more valuable on a wider scale than simply being a superconductor. If they can raise the temp of superconductivity, while maintaining this property, it has the potential to be a game changer.

a reply to: surfer_soul


Eh sort of most of them were looking for riches; lead being more abundant. As a metaphor it was the philosophers stone... the thing of attenuation for reason and correct understanding. The Shiva lingum is "by way of mouth" many erringly think of it as a penis. It is a shirne for mining gold from the river ganges... blue body signified silver the wellspring from which those riches sprang drink too much silver and it it will destroy all life inside the body other than the cells of course. Part of the old rituals of inner purification mercury will pull gold out of silt gather all the small flakes together, mulslin "muslim" cloth will squeeze the mercury out and well as part of the silk roads even finer could be gained than the coarse muslin.

Filters once it lands in an ear it then goes through that thing called a brain, no need to sort or contrast or compare unless writing a teasite or treaty to allow trade to flourish or flower so that those wheeels could keep spinning. Seven and the eighth of course the true wealth. When that knowledge returns it is an echo, a vault to which such riches returned...

People claiming knowledge as ones wealth is like stamping their face on money or coinage to fraction wealth, knowledge used to come at a very high price some was given in servitude... the change to learn at the feet of a learned master. Of course life itself springs forth like water... the heaviest sinks to the bottom and the richest rise to the top.

Just a metaphor of elements when taken into people over the earth governments heirarchies or heirs with an arch a doorway into and out of which to pass or call home. This was taken further as the ark which meant covenants and convents of manners of convention.

Beasts of burdens to carry riches and well they even went so far and many still do to carry ignorant ideologies using women as beasts of that burden.

How to weigh all of that on the scales of equality... volition is close to vocation.

Cause leads to effect, how can one find the first cause being a larger part of a chain reaction? Dependent arising has to do with conditions, conditioning... it is brought forth to metal with heat and air by way of wood in china the fifth element is children or wood the labor of the entire mother through heirs and many simply put on airs.

Distilling is the vapour of a closed system to render down in strength so that a currency lasts.

Conservatories and conservation some look to stretch a dollar without printing it using rubber trees, so using rubber to balloon those tires became a new locomtion after crossing the vast oceans... used to be skirting lands, having crows to carrion or carry on as they will fly towards land and if none they will return.

We all used to be married as a people across all lands... and honestly still are; however, power is kept to those knowing and those unknowing still trod on.

As we fraction supply after supply in controlled world capitalizing the various ideologies are shifted through the sands of time; writing and rewriting history... leave the past past and the entire future can get over itself.

Why? Only a pregnant one can be said to be truely expecting the father of the child heped concieve and if not then like an animal poorly planned.

Many humans live like animals having come from them in hard fought paths of evolving or adapting to adversity saying one has to climb through university or universality to be an illuminary is true and yet not... we have brought ideological blight across the face of the entire earth in ideas of domination or dominion ano dominae; one dominance over time.

Syncretion? no. Thats the illsusion the delusion that the entire world and all it's inhabitants must move on one time like a hive... wake up and stick to your regularly sheduled programming. Or else one is a rogue, a ruffian, an outsider, blah blah blah. No one wants your hive your herd except in due trade yet it is tirade after tirade and torrents of words.

Like people being so attached to words as a form, it is a link of slavery a trigger a slave chain to pull and fight against. Same as time relative to the observer of it.

I have been called so many names over time; to which should I come or go to? None as it is free will. Carry a thing called a god and do you expect the devil to be at your feet being such a slave?

Doing work for works sake is where a pleasure and passion come from... The one called Christ was supposed to be a carpenter he lost his passion for wood the fifth element but yet how to walk on water boats metphors seeing those enjoying the fruits of his labor he called to those using his creation with passion to use their nets on something else...

While people in Rome etc lay around enjoying the spoils of labor and sending others off to war setting up a trade center and saying all roads must pass through Rome is what built it up as an empire; like any town any city seen today. Where are all the deer paths, wagon trails? People are driving on them and yet those deer paths still exist, the goat paths where the mountainious regions climbing to the inassecible required taking one of those with you.

Devining sheep lol, no it was to milk the goat so one could eat cheese and butter churned from the walking and drink the milk gather plants along the way from bread, sold when coming across others for their table without having to beg from theirs.

The idea was freedom mendicancy or mending paths with understanding, respect, benevolence. Thats all the eightfold path was in Buddhism travel all roads by those rules... and meditate on them in observation and one will never be a subject or slave. If one is found as such then be the bull to the brahman then one will find freedom eventually or rise through the ranks cherished in the path of service.

Of course over time all of that was twisted to culture and custom... but yet the core remains. We as life clinging to the elements as firmament also use them internal and external as support. So how can one ever be without or have lack?

It is impossible from smallest to largest all are constantly and continually employed in some manner known or unknown seen or unseen.

Thats just the way it is and always has been as is is alwalys is, is can never be anything else other than is. Sure it can be changed and disambiguated but yet when it becomes a direct pointing. It becomes known and remains simply is. No matter the being.

Cest la vie mon frere.

a reply to: TEOTWAWKIAIFF


Indeed think of them as marbles on a track too much angle no way over the hump to go back around and over again but roll back... so yes the angular momentum is very important even on that scale.

a reply to: Krakatoa


There has been an update to your post that is even better than that magic angle of 1.1 from your OP.

In April 2018, a group at MIT in the U.S. showed that it is possible to generate a form of superconductivity in a system of two layers of graphene under very specific conditions. To do this, the two hexagonal nets must be twisted against each other at a 1.1 degree angle. Under this condition, a flat band forms in the electronic structure. The preparation of samples from two layers of graphene with such an exactly adjusted twist is complex, and not suitable for mass production. Nevertheless, the study has attracted a lot of attention among experts.

At BESSY II, the physicists are able to scan the so-called band structure of the sample. This band structure provides information on how the charge carriers are distributed among the quantum-mechanically permitted states and which charge carriers are available for transport at all. The angle-resolved photoemission spectroscopy (ARPES) at BESSY II enables such measurements with extremely high resolution.

Via an exact analysis of the band structure, they identified an area that had previously been overlooked. "The double layer of graphene has been studied before because it is a semiconductor with a band gap," explains Varykhalov. "But on the ARPES instrument at BESSY II, the resolution is high enough to recognize the flat area next to this band gap."

"It is an overseen property of a well-studied system," says first author Dr. Dmitry Marchenko. "It was previously unknown that there is a flat area in the band structure in such a simple well-known system."

This flat area is a prerequisite for superconductivity, but only if it is situated exactly at the so-called Fermi energy. In the case of the two-layer graphene, its energy level is only 200 milli-electron volts below the Fermi energy, but it is possible to raise the energy level of the flat area to the Fermi energy either by doping with foreign atoms or by applying an external voltage, the so-called gate voltage.

The physicists have found that the interactions between the two graphene layers and between graphene and the silicon carbide lattice are jointly responsible for the formation of the flat band area. "We can predict this behavior with very few parameters and could use this mechanism to control the band structure," adds Oliver Rader.

They wanted to measure bi-layer graphene and see what exactly is going on with the layers. Using their ARPES instrument they found a structure, a "flat area", that as noted, can be doped to push it over the Fermi energy hump!

If that happens, we might be closer! And guess what? They did not need to twist it in some magic angle because it was there to begin with!

A silicon carbide crystal is heated until silicon atoms evaporate from the surface, leaving first a single-layer of graphene on the surface, and then a second layer of graphene. The two graphene layers are not twisted against each other, but lie exactly on top of each other.

(Same source)

Which means it should be able to be mass produced in strands! Link the strands together (somehow) and you may have your lightly doped graphene superconductor! Maybe even at room temperature!

arXiv.org, 1801.09376 (pdf): Observation of the Meissner effect at room temperature in single-layer graphene brought into contact with alkanes.

Meissner effect is observed when the magnetic field is kicked out when a superconductor is reaching its Tc.

Wonder what they are going to dope it with? I wonder how long it has been known (black project)?

a reply to: Krakatoa


Here is the actual paper... in full!!

Scienceadvances (advances.sciencemag.com), Nov. 9, 2018 - Extremely flat band in bilayer graphene.

Not paywalling this means something!

3C-SiC was used. That is 3-layer graphene on the silicon carbide crystal. They also tried a couple other configurations. Here's their conclusions...

Our high-resolution ARPES study of BLG on 6H-SiC shows that the band structure around the Embedded Image point has neither the predicted parabolic nor the Mexican hat shape but stays in an intermediate stage causing flat band dispersion. The band has a number of unusual properties such as very high photoemission intensity, very high DOS without detectable dispersion and narrow width, contribution of only one graphene sublattice, and the absence of photoemission interference effects. We explain the mechanism of the flat band appearance and show that, by influencing sublattice and interlayer asymmetries, one can radically control the band shape and its properties. Indications of enhanced electron-phonon coupling, together with the discussed possibility of creating and controlling the flat band, are related to the question of high-temperature superconductivity in graphene- and graphite-based systems, while, on the other hand, the mechanism of the flattening of the dispersion is more universal and could be used in transport applications beyond BLG.

(same source)

BLG is "Bi Layer Graphene". ETA: DOS - "density of states" (and not the operating system we used to luv!)

The part I emphasized is very interesting! That means control of the flat band can be done in other 2D substances.

We are standing on the edge of something wonderful!

My god. It's full of stars!

a reply to: Krakatoa


I don't think this will be 5 - 10 years. I think it has just started!

This is from last year where they figured out how to dope single layer graphene (SLG) and BLG.

phys.org, March 2017 - Decorating single layer and bilayer graphene with useful chemical groups.

And that was with large molecules. If it is single particles they have been doing that for years.

Over the past years, theory has consistently predicted flat band superconductivity accessible by doping or gating and with enhanced critical temperature.

Source: Science Advances article

Squee!