silicon carbide

A thin layer of indium arsenide lies hidden under a superconducting film, like a voice beneath the noise of a crowd. In such a hybrid, current takes the path of least resistance and flows almost entirely through the metal, leaving the semiconductor inaudible to standard probes.

A metal made of five different atoms is like a soup with bits of carrot, peas, potato, onion, and meat floating in it. Each bit is its own element: chromium, vanadium, titanium, niobium, and tantalum. Such an alloy is called high-entropy: there is no single order, and the atoms are mixed almost randomly.

Inside a diamond anvil cell, squeezing a sample with a force millions of times greater than atmospheric pressure, a thin film of lanthanum meets hydrogen. The hydrogen comes from ammonia borane — a powder that, when heated, releases its hydrogen like a sponge releasing water.

An ordinary wire heats up when current flows through it — some energy is wasted. A superconductor lacks this flaw: electricity flows through it without loss, like water through a perfectly smooth pipe. The trouble is that most superconductors require either very low temperatures or colossal pressures, like those found in the depths of planets.

A bridge where pedestrians and cyclists flow together without getting in each other's way. That's roughly how hybrid systems of superconductors and semiconductors work: the former carry current without loss, the latter control that current.

A microchip the size of a fingernail gives off as much heat as a small light bulb. Getting rid of that heat is like trying to cool a cup of hot tea with a teaspoon: the insulating material around transistors is usually a poor heat conductor.

A ceramic plate as thin as a soap film, and through it flows current with zero resistance. That's the superconductivity achieved in nickelates, relatives of the famous cuprate superconductors. Previously, this required enormous pressure, comparable to that at the ocean floor.

A speed of 7,5 kilometers per second is the threshold beyond which a cosmic collision turns dust grains into a chemical reactor. In the interstellar medium drift tiny cosmic dust grains — the legacy of dying stars.

A potter uses a sharp stylus to trace a pattern on a still-damp clay tile. One wrong move, and the line blurs, the tile cracks. Physicists work with films of the high-temperature superconductor YBCO (a compound of yttrium, barium, copper, and oxygen) in much the same way.

In murky mud, between two electrodes, long chains of bacteria line up: each one as thin as a microscopic cable. Every such filament conducts current over a full centimeter, a true marathon for a microbe.

Superconductors conduct current without loss, but usually require extreme cold. Hg1223 — a mixture of mercury, barium, calcium, copper and oxygen — breaks the rule: it stops resisting current already at –139°C. The secret is that the strong electrical repulsion between electrons forces them to pair up.

The young super-Jupiter TWA5B, a scorching ball 25 times Jupiter's mass, floats just fifty light-years away. Its faint infrared glow long hid its chemical makeup. Now, high-resolution spectroscopy with CRIRES+ has registered the ghostly trace of SiO — silicon monoxide.

Two white sheets lie in the sun — one rough, one smooth. Which one heats up less? The rough one scatters light more strongly, so it seems it would stay cooler. But if the coating is made of many transparent glass beads, the logic changes. Light wanders through it like in a thick fog, and at some point it stops noticing individual droplets.

Imagine a sandwich where the bread is made of copper oxide layers and the filling is a thin layer of strontium ions. That's the infinite-layer cuprate, the simplest version of superconducting ceramics, conceived nearly 40 years ago.

A layered cake of atomic planes of nickel and oxygen: that's how bilayer nickelates are built. Two such planes are separated by a spacer layer. If an oxygen atom sits in that spacer, it acts as a bridge: it links the layers and triggers a state in which electrons move without resistance.

Silicon carbide is the material used to armor electronics. It withstands heat, impacts, and radiation like the ceramic tiles on a spacecraft's heat shield. But even this armor has a weak spot: ordinary metal contacts quickly degrade under X-rays.

A mosaic floor made of many small tiles, each turned in a different direction. It seems that any pattern trying to cross such a floor would get scrambled and vanish. That's how people usually think about disorder in crystals: if atoms aren't arranged in a perfect lattice, delicate quantum effects should fall apart.

A crowd on a narrow street moves slowly because people bump into each other. In silicon, heat is carried by similar 'shoves'—atomic vibrations called phonons. If you cut tiny holes in a silicon film, phonons will bump into them like pedestrians into lampposts, and heat will flow worse.

A superconductor is a material through which current flows without loss, like water through a perfectly smooth pipe. But to make the pipe perfect, you have to cool it to very low temperatures. Physicists have long been looking for ways to make such a pipe at warmer temperatures, and one clue is the quantum critical point.

In a strong magnetic field, electrons in a thin metal film move along circular orbits. When the film thickness is comparable to the size of such an orbit, the resistance starts to oscillate: these are Sondheimer oscillations, known since the mid-20th century as a purely geometric effect.

An ordinary transistor in a phone is made in a vacuum chamber, where atoms are deposited layer by layer. Expensive and slow. But indium oxide can be printed like ink — from a drop of liquid metal that, in air, coats itself with a thin oxide film. The authors took indium, melted it, and rolled it over a substrate at 250 degrees.

Superconductivity is when electric current flows without losses, like water through a perfectly smooth pipe. It usually occurs at very low temperatures, but there are materials where it appears at higher ones.

A piece of metal heated at one end produces a weak electric current: this has been known for nearly two hundred years. But what if, instead of a simple metal, you take a layered "sandwich": a superconductor, a thin insulator, and a flat layer of electrons?

Superconducting circuits often rely on Josephson junctions — places where current flows without resistance through a thin barrier. Typically, this barrier is an oxide layer, but its properties are hard to control at the nanoscale. In this new work, the barrier is a thin layer of niobium or titanium nitride sandwiched between niobium layers.

A piece of aluminum alloy is heated, and it quietly tells you about its strength. You just need to listen to that story in how the metal absorbs heat. The usual way to find out how strong an alloy is — pull it until it breaks. That takes time and destroys the sample.

A piece of silver antimony telluride is like a sponge: it readily soaks up heat and turns it into electricity. Such materials are called thermoelectrics, and they already work in space probes and car refrigerators. But if you squeeze this sponge, it starts behaving like a superconductor — current flows with zero resistance.

Light that has traveled to us for nearly 14 billion years is like an old photograph whose details emerge with careful processing. The cosmic microwave background (the afterglow of the Big Bang) holds the imprint of the universe's first moments, but its signal is faint and distorted.

A power transistor made of silicon carbide operates under voltages thousands of times higher than what comes out of a wall outlet. If the field inside it becomes uneven, the device burns out. Previously, this field was invisible: it is too strong for ordinary sensors, and the device must remain under voltage.

A solid electrolyte is like a sponge for lithium ions. In a regular lithium battery, ions float in a liquid, like fish in an aquarium. In a solid-state battery, they have to squeeze through the crystal lattice, like through narrow corridors.

The microchips inside smartphones and computers are getting denser: billions of transistors are packed onto a sliver of silicon the size of a fingernail. When they work, they give off heat like tiny stoves. If that heat isn't drawn away, the chip overheats, starts glitching, or fails outright.

On the surface of ordinary table salt, a ring of carbon atoms grows, like a bracelet assembled link by link. Only here the links are not metallic but carbon, and they are joined not by a jeweler but by the tip of a scanning microscope.

A thin film of niobium and tin conducts electricity without resistance — until you make it really thin. Then it suddenly becomes an insulator. A team of physicists tested what happens when you add a bit more tin to the film than the formula calls for.

A quantum computer is like a musical instrument: even a tiny scratch on a string ruins the sound. Instead of strings, we have superconducting resonators — thin traces of titanium nitride on a silicon wafer.

When light hits a semiconductor, it can knock out an electron, leaving behind a hole. The electron and hole attract each other and form a pair — an exciton. This pair can re-emit light, but not immediately: first, it exchanges energy with vibrations of the crystal lattice — phonons.

Hydrogen is a clean fuel: when it burns, it produces only water. But to extract it from water, you need to break the strong bond between hydrogen and oxygen. This is usually done with platinum, an expensive metal.

A quantum bit is like a spinning top that must keep spinning steadily for a long time. In germanium, researchers have learned to set such tops spinning, but the floor around them is always trembling: electrical noise knocks the spin off course.

A regular superconductor and a magnetic field are like water and fire: the field tears apart the electron pairs that carry current without resistance.

An ordinary wire heats up when current flows through it. A superconductor doesn't. But almost all known superconductors require either very low temperatures or enormous pressures, like those deep inside planets. Scientists have long searched for a material that avoids these extremes.

Electronics get hot. The more powerful the processor, the more heat you need to get rid of, or it will fail. One bottleneck is the boundary between two materials: heat hits it like a seam between tiles and slows down.

Sunlight hits a rooftop, and electrons are born in a thin film. They must reach the wires before they cool down and lose their energy. In tin sulfide, a cheap and accessible material for batteries, this sprint and cooldown has now been captured with unprecedented sharpness: frames follow every billionth of a billionth of a second.