Room Temperature Superconductors#
This Changes EVERYTHING! - (LK 99)
Physics has always been one my favorite fields of study. Everything from how planes fly, to how solar panels work... but in the quantum world, things get weird and interesting. This new breakthrough coming out of Korea has the potential to be one of the biggest breakthroughs of the CENTURY. A room temperature, ambient pressure Superconductor. So how exactly does it work, is this research legit, and why does it matter? Let's figure this out together!
Introduction#
New research on a room temperature superconductor has the scientific community abuzz, and for good reason. This will be one of the greatest breakthroughs in the history of physics. We're talking instant Nobel prizes for the people involved and billions and billions of dollars - game-changing stuff. But there's been some controversy around superconductors in recent memory, and the bigger the claim, the more we have to be skeptical. So, what's really going on? Is it really legitimate, and what could this mean? Let's figure this out together.
Alright, so why does this matter? Well, five percent of the energy produced in the US is wasted during transmission through power lines. That's enough to power all seven Central American countries four times over. With superconductors, you have basically no resistance, no losses, and near-perfect energy transfer. That would be one of the game changers, and there's a whole bunch more, but we'll get back to that in just a second.
What we Know#
A team of researchers from South Korea claims they have achieved a superconductor material codenamed LK 99 at room temperature and atmospheric pressure. Superconductivity was first discovered by Dutch physicist Heike Kamerlingh Onnes back in 1911. Like ferromagnetism and atomic spectra lines, superconductivity is a phenomenon that can only be explained by quantum mechanics. Now, that is a key factor in this story. It kind of ties it all together, and we'll get back to that multiple times throughout this story.
What is a Superconductor?#
The key requirements to be classified as a superconductor are the following: one, the electrical resistance vanishes, and two, magnetic flux fields are expelled from within the material. Don't worry; we're going to explain both principles. If you want to transfer electricity through a wire, you want something with as low a resistance as possible. Here's a table of some of the lowest resistances among metals. Silver is really low, but it's super expensive, so the worldwide standard is copper. To be classified as a superconductor, resistance has to be below 1 times 10 to the negative 13 ohm meters. This means that even copper has 168,000 times higher resistance than a superconductor. If you have a toaster at home and see those glowing red-hot coils, that's probably nichrome, a material that's really high resistance. Now, it's high on purpose because it's built to waste energy as heat to toast your bread. But here's the crazy part - it's only 66 times higher resistance than copper. That means our worldwide standard material, copper, is closer to a horrible conductor than it is to a superconductor. One of the easiest ways to understand resistance is by thinking about an airplane flying through the air. A bad conductor, like our nichrome in our toaster, is like slapping engines on a big refrigerator. Yes, it'll fly, but you'll be wasting a ton of energy to move it around. And then copper would be like a Boeing 787 Dreamliner with a blunt nose and tapered tail to absolutely minimize drag. This would require much less energy. And then our superconductor would be like that same Boeing 787 climbing out of the atmosphere and into outer space where there are no air molecules at all. Sure, I understand there would be no oxygen for the ingestion for the engines, and there'd be no molecules for the lift over the wings, but if you think about it that way, that 787 would just fly at that speed indefinitely because there would be no losses. And that's kind of what's happening with a superconductor. We'll talk more about the benefits in just a bit, but first, let's talk a little bit about the drama and controversy surrounding this breakthrough.
The Controversy#
Now, there is a great deal of excitement, uncertainty, and doubt surrounding this discovery. In science and engineering, the greater the claim, the greater the skepticism you need to approach it with. But there's added skepticism through no fault of their own. Ranga Dias, a physicist at the University of Rochester in the U.S., had a paper published in Nature in 2020. In the paper, he and his colleagues claim to have created a room temperature superconductor from a combination of carbon, sulfur, and hydrogen under extreme pressure. The publication Nature later retracted that paper in 2022 after other researchers were unable to replicate the results. Concerns were raised about how the raw data collected from the experiments was processed. Basically, they were saying there's some fabrication, potential fraud, and other issues. The scientific journal Physical Review Letters (PRL) is reportedly preparing to retract a second paper by Dias on the electrical properties of manganese disulfide. According to Nature, PRL is investigating allegations of data fabrication and falsification combined with concerns raised by the first retraction. But Dias's team only solved the temperature problem; their superconductor still needed super high pressures to work, so it wouldn't work in this room, for example. The temperature would be okay, but you would have to have incredible high pressures. Now, this latest breakthrough that we're talking about today from Korea claims that it works not just at room temperature but at atmospheric pressure. That is a double game changer, and it's become controversial because of previous claims by Ranga and others, and it's got the scientific community's guard up. It would be like starting a new crypto exchange after the FTX debacle. It doesn't mean that it's not above board, but it's going to get much more scrutiny. No one is accusing the latest research team of being fraudulent, at least not yet, but there are some interesting things going on. For example, two papers hit the internet within two hours of each other - the first, "Room Temperature Ambient Pressure Superconductor," and later, a second paper titled "Superconductor Showing Levitation at Room Temperature and Atmospheric Pressure and Mechanism." Now, these papers weren't published to Nature or Science but a pre-print server called arXiv. This isn't in and of itself a bad thing; it just means that further corroboration and verification are required for wider scientific acceptance. If this turns out to be real, this is an automatic Nobel Prize; they have it locked up. But interestingly, it can only be shared among three people. The emergence of two papers and the mad dash to make sure people are getting credit is actually a good sign that there might actually be something to this claim. So here is a list of the three authors on the first paper and the six authors on the second. It'll be really interesting how all the credits and stuff work out and whose names get attributed to the Nobel Prize if that's on the horizon.
The Timeline#
The timeline of how we reached this breakthrough. Sukbey Lee met Jihoon Kim in 1996 and got their first taste of superconducting materials. In 1999, Lee finishes his PhD and sets up Q
Center, which works on Quantum Computing and has direct ties to superconductors. The first tie to quantum computers. By 2017, they were getting close to having something and started raising money. In 2018, Yang-Won Kim, a physics professor, comes on board part-time as her CTO. In 2019, they confirmed that they have a room temperature superconductor working and fought for Korean patents for production of low resistant ceramic compound. In 2020, Covid happens, and they go heads down and finally isolate the superconductor, obtain its crystal composition, and analyze the characteristic structure. They make a submission to Nature and get rejected because of the Ranga Dias controversy. It's kind of a tough time to publish papers. They were asked to publish locally and get it peer-reviewed to help with credibility on the world stage. They bring on Hyun-Tak Kim, research professor of physics at William and Mary, to help in further test and validate their claims. In March 2023, they filed for their international patent application, and, of course, in July, they published the papers that we're here talking about.
The Science#
Okay, now let's look at the key to such a major breakthrough comes from an unconventional form of superconductivity. In a normal conductor, free electrons within a material move around in a crystal structure and bounce off atoms and ions along the way. This creates resistance that makes them lose part of their energy, which is dissipated as heat and absorbed in the larger lattice. This is why resistivity is very clearly mostly tied to temperature because the higher the temperature, the more ion motion there is and the more collisions and losses there are. And this is why normally superconductors have to be cooled to near absolute zero. But in a superconductor, this doesn't happen. The conventional explanation is the Bardeen-Cooper-Schrieffer Theory or BCS Theory from 1957. This theory explains that superconductivity is caused by the formation of Cooper pairs, which are pairs of electrons with opposite spins that are loosely bound together by a weak attractive force. Cooper pairs are different from normal electrons in that they can condense into a coherent wave of superconducting electrons. These pairs flow through the material as one instead of moving as multiple free electrons. It's like someone guiding a group of people with a thin rope through a dark forest as opposed to blindfolding everyone, putting them in the middle of the forest, and hoping they get to the other side without running into trees. But LK 99 is like teleporting from one side of the forest to the other. The problem with Cooper pairs is that the string that keeps them together is weak, and any minor thermal vibration in the crystal lattice will break them apart. So you need very low temperatures for conventional superconductors to work. But LK 99 doesn't rely on weak Cooper pairs; it relies on a new form of superconductivity coined "superconducting quantum wells," which enables it to work at much higher temperatures than ever thought possible in the past. Superconductors only worked near absolute zero, where you needed liquid helium to cool them. But then there was a new breakthrough of high-temperature superconductors, but they were still incredibly, incredibly cold, and you would need to be around negative 200 degrees Celsius, and you could cool them with liquid nitrogen. But LK 99 can work as high as 400 degrees Kelvin - that's 260 degrees Fahrenheit or 127 degrees Celsius. That is a new temperature range that scientists didn't even think was possible based on the old theory of Cooper pairs. So, how does it work? Well, it has everything to do with chemical structure. LK 99 is a solid made by replacing some of the lead atoms in lead appetite with copper atoms. When we replace one of the outer lead atoms, which forms a framework of the structure, with a copper atom, the entire structure shrinks by about half a percent because copper is smaller than lead, and the whole thing gets a bit distorted. This shrinkage causes stress on the internal column of lead atoms and creates superconducting quantum wells along the column. Electrons can pop in and out from those magical portals through quantum tunneling, avoiding all obstacles and, therefore, showing no resistance. One thing I found interesting about this paper is that it's explaining superconductivity in a different way, yet it still works for other superconductors. It basically says that what you need to do is contract and distort the crystal structure to make these quantum wells. You can do that by lowering the temperature or increasing the pressure, which we've done in the past. But the moment that pressure drops or the temperature increases, your superconductor stops superconducting. The new way to do this is to change the structure from within, and just by adding this copper and increasing that stress, it appears they've done it. Now, this is at the heart of what they've accomplished here. What's amazing is it's not particularly exotic or hard to do - these are things that we've been doing for a long time. I honestly think this will spark a new wave of research, and before long, we'll have tens, if not hundreds, of new ambient superconductors for all sorts of applications. But how good of a superconductor is LK 99? Not all superconductors are the same, and scientists classify them according to several performance metrics.
Open Questions#
First, there's resistivity. A low resistivity is what makes a superconductor. However, no matter what you've heard, it's not exactly zero. The threshold for material to be considered superconducting is a resistivity of 10 to the negative 8 to 10 to the negative 9 ohm centimeters. As you can see in this graph, LK 99 shows a maximum of around 4 times 10 to the negative 9 ohm centimeters, but in general, it's lower than that, around 10 to the negative 10 ohm centimeters. Then there's critical temperature - this is a temperature at which superconductivity is lost, and that's what defines a high or low-temperature superconductor. This graph shows the measured voltage for different levels of current inside LK 99 at different temperatures. The horizontal flat part is where it acts as a superconductor. Notice that as the temperature increases, that horizontal range gets smaller. For example, at room temperature (298 Kelvin), it has a really wide band of currents that it can support, but that shrinks the higher the temperature gets, all the way to this tiny range of superconductivity when the temperatures reach almost 400 Kelvin. But let's take a minute to appreciate that even at 400 degrees Kelvin, it's still superconducting, at least a little, and that was unheard of before, especially at ambient pressure. Lee and his team were only able to reach 400 degrees because their equipment couldn't go any further. Can you imagine the industrial applications of a superconductor working at over 400 degrees Kelvin? It would have one thing that was bugging me about superconductors: if there's no resistance, can you get an infinite current inside a superconductor? Can I use it to charge my car in, like, a second? And I found the answer is no. Notice that high or low currents in the same graph, there's a jump
in voltage that signals the loss of superconductivity, due to quenching, which happens when the current inside the conductor generates the magnetic field that breaks superconductivity. The current at which that happens is called the critical current or IC. Here is a plot of the critical current versus temperature for LK 99. Really, what it tells us is that around room temperature, that critical current was what we saw earlier, around 250 milliamps. But that value quickly drops as the temperature increases. So really, anything higher than that, and it turns into a regular metallic conductor. Finally, we have the famous Meissner effect or superconducting magnetic levitation. The team of researchers actually managed to make a coin-sized sample levitate, well sort of, on top of a powerful permanent magnet. And you can see that there is definitely something pushing up, but is it floating? I'll let you be the judge of that. The Meissner effect is explained by the formation of little loops of electric current, called screening currents, on the surface of the superconductor. These currents are like electromagnets that generate a magnetic field that exactly cancels out the external magnetic field, so it levitates. This principle is what makes superconductors attractive for high-speed maglev trains. So at this point, you've got to be wondering what's the catch? Rare materials, complex processes, toxic chemicals? No, this superconductor is actually pretty easy and cheap to make. All you need is lead oxide, lead sulfate, copper powder, and phosphorus. The entire synthesis is a three-step solid-state process where you put the ingredients inside a sealed quartz tube and cook it in a lab oven at less than a thousand degrees Celsius for about four days, and it's done. Once you get this ugly-looking rock, you can use it as is, or you can make thin films with it using thermal vapor deposition. This is standard technology in industries like electronics, optics, and aerospace. This is seriously game-changing technology. But there are many questions that are still unanswered.
Why this Matters#
Is there a way to combine several conductors to achieve higher currents? I mean, 300 milliamps isn't a lot, especially for industrial purposes and power transmission. Can you imagine charging your Tesla on 300 milliamps? These measurements were made on a tiny sample. What would happen when we make this into a 12-mile track for a maglev train? Would it still work? How will this scale? And what about joints? Can you connect two pieces of LK 99, and have the superconductivity pass from one to the other, or does it have to be one constant solid piece? These are things we just don't know yet, but if these guys' claims are legit, which they seem to be, we'll know very soon. And when we do, we'll have a follow-up video and we'll bring you up to speed on all the new findings. This is very early on, but it's very promising. The next steps are going to be critical. They have provided their work for the entire scientific community, and a lot of labs and research facilities around the world are trying it for themselves. The next step is corroboration and replication. Can other people do the same thing? This is part of what makes the scientific process so powerful - repeatability. If only one person can do it, odds are there might be some foul play. But if others in the scientific community can start to test it, which they will be doing in the coming weeks or so, we'll do follow-up videos and tell you how this plays out. The amazing part is that this is not exotic. The materials required are pretty common; lead is a fairly common material in the Earth's crust, and so are everything else required. Even the machines and fabrication processes are pretty straightforward. So, there should be really no reason why we shouldn't have an answer in the next month or so. Now, let's assume that this actually is legit and all their claims are true. What could this mean for the world?
Why this Matters (Continued)#
This would have a deep impact on almost every engineering discipline. One of the key benefits of superconductors is confinement. Let me give you two examples. The first is an MRI machine. MRI machines produce such strong magnetic fields that it's important to confine those fields to the room; otherwise, they could be harmful to pacemakers or people that didn't sign up for an MRI. The first MRI machines used around 40 tons of iron to line the rooms they sat in to shield the magnetic fields. This makes it incredibly expensive and difficult to install MRI machines. But modern MRI machines use secondary electromagnets to operate in a superconducting state. They have zero resistance and can carry large amounts of current without overheating. The only catch is that these superconductors need to be cooled with liquid helium down to negative 269 degrees Celsius or 4 Kelvin - that's 4 degrees from absolute zero, and that is the largest part of the cost and maintenance of running MRI machines. But with room-temperature superconductors, system design would be simplified dramatically, and MRI machines' upfront and operational cost would be slashed significantly. Imagine MRI machines available for a lot more than just the most critical things and not having long wait times. Medicine - game-changer. How about nuclear fusion reactors? Again, the high-energy plasma that is produced has to be confined, which is currently done with superconductors and, again, at very low temperatures. This energy input to keep that superconductor material cold could be done away with. In a world with room temperature superconductors, the Meissner effect would even allow for ultra-efficient, low-cost maglev trains, like we mentioned before. You wouldn't need neodymium or other rare earth metals; you could use this room-temperature superconductor. How about ultra-efficient electric vehicles that don't need battery or motor cooling? All the heat that is produced in copper from running windings inside an electric motor has to be cooled because they're not perfectly efficient and do have some resistance, and this reduces efficiency. Both because one, you're wasting some of that electricity as heat, and two, you have to run pumps and heat exchangers to handle that heat - both of those things use energy that aren't propelling your car forward. Superconductors are also able to maintain a current with no applied voltage. Experiments have demonstrated that currents in a superconducting coil can persist for years without any measurable degradation. Experimental evidence points to a lifetime of at least a hundred thousand years. So, might we be on the brink of a whole new industry of room-temperature superconductor batteries? That's a video all by itself for another day. But by far the most fascinating application has to do with the fundamental research Suk Bay Lee was working on at Q Center, and that's quantum computers. If you've ever seen a picture of a quantum computer in all its glory, it is a really beautiful machine. The chip itself is actually really small; the rest of the machine is entirely made and there for keeping it cool. Room temperature SCS would be one of the biggest game-changers, and it would allow a world where we could have quantum computers on our phones and our laptops. We also mentioned power distribution, right? That's another one. Let us know in the comments below if there
are other things you think will be positively impacted. I want to know! So that's what we know about the recent room temperature superconductor discovery. How do you feel about it? Are you excited? Are you skeptical? Do you think it's real? Do you think it's too good to be true? Or do you think it's the end of the world? Like so many people, I do think it's a little bit of a miracle, but we're very skeptical.
Documentation By: Raymond C. TURNER
Revision: March 25th, 2024