In a groundbreaking experiment, a team of scientists from MIT has managed to do something remarkable with electrons – they’ve trapped them in a three-dimensional crystal, a bit like putting cars in a parking lot so they can’t move around.
This achievement is a first and could open doors to exciting technological advances, including materials that conduct electricity without any waste.
Electrons are tiny particles that move around in materials, carrying electricity as they go.
Usually, they’re like busy commuters in a big city, moving fast and ignoring each other.
But in certain cases, they can be made to act together, almost like they’ve become a group of synchronized swimmers.
When this happens, they form what scientists call an “electronic flat band,” which sounds pretty technical, but essentially means all the electrons are sharing the same energy level, just like a flat road makes all cars drive at the same level.
Why is this “flat band” important? When electrons behave in this shared way, they start to notice each other more and can start doing quantum physics tricks, leading to very special states of matter.
These states can make materials do amazing things, like conduct electricity with no resistance at all (superconductivity) or have unusual magnetic properties.
The MIT physicists made a crystal that acts like a 3D maze that traps electrons. This maze is inspired by ‘kagome’, a Japanese basket-weaving pattern.
Imagine electrons as tiny balls rolling around on this woven maze – they end up getting stuck in the little pockets of the pattern.
The researchers discovered that in this kagome-like pattern, the electrons don’t jump around from atom to atom; instead, they settle down in one place, all at the same energy level.
The cool thing is that the scientists think this can work with any atoms, as long as they’re arranged in this special kagome pattern.
This discovery, published in the prestigious journal Nature, is a big deal because it could help us make new materials that could one day be used for things like ultra-efficient power lines or super-advanced computers.
Before this, researchers had managed to get electrons to form flat bands in materials that are only one layer thick – like a sheet of paper.
But in those cases, the electrons could sometimes escape out the sides, like water spilling over the edge of a table. The big leap here was trapping them in a full 3D space, which is more like putting water in a cube and freezing it into an ice cube – it’s much harder for anything to escape.
Making this 3D crystal wasn’t easy. The team compared it to how nature makes crystals. They melted down some elements – like calcium and nickel – and cooled them to form a crystal with the kagome pattern.
Then came the tricky part: proving that the electrons were really trapped in this flat band. To do that, they had to knock electrons out of the crystal using light and measure their energy.
But because the surface of the crystal was really bumpy, like a mountain range, it was tough to do. They overcame this by using a super-special light technique that can ‘land’ on tiny, specific spots on the surface, just like a helicopter landing on small helipads on a mountain.
When they used this technique, they found that, yes, the electrons in the crystal were all at the same energy level, showing they were trapped as they hoped.
Even more exciting, when they swapped in different elements like rhodium and ruthenium, they could turn the crystal into a superconductor, which means it could conduct electricity perfectly, without any resistance.
This research isn’t just for the fun of science – it could lead to materials that change the way we use and save energy. Now that they know it’s possible, the challenge for scientists is to make these materials even better, maybe even finding a way to make superconductivity work at higher temperatures, which would be a huge step forward for technology.
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Source: MIT.
