Superconductivity cond-mat.supr-con

A magnetic field of 8 tesla is 200 times stronger than Earth's field. Under such a field, superconductivity in a thin film of palladium ditelluride not only survives but persists down to 20 millikelvin, which is a hundred times colder than outer space. For comparison, a thick film of the same material has a critical field 80 times smaller.

Deep inside a superconductor, electrons pair up into Cooper pairs and glide without resistance. But if a vortex appears in this perfect order, a tiny region where superconductivity vanishes, special excitations emerge there: Bogoliubov quasiparticles.

Run a current through a contact between a superconductor and a ferromagnet, and you will hear the whisper of the quantum world. In the lab at 0.3 K, that whisper turned into a roar: the shot noise—electrical noise due to the discreteness of charge—was a hundred times louder than theory allows for ordinary contacts.

In photometry (the measurement of light), catching individual microwave photons was long impossible: their energy is on par with the thermal jitter of atoms.

Measured dipole moment of tantalum-181: 3.39 × 10⁻³² e·cm — like spotting a one-atom shift across the entire Solar System. An ordinary atomic nucleus is perfectly balanced, like a spinning top. In tantalum, that balance is broken: the positive and negative charges are slightly offset from each other.

In diamond, you can embed a “spy.” Simply replace a carbon atom with nitrogen: you get a defect that responds to magnetic fields and sends a light signal.

Matter is like a house. In some rooms, there is the strict order of a crystal, where every atom is in its place. In others, the chaos of superfluid helium, where atoms forget about their neighbors.

All matter, from stars to humans, is built from particles that in the Standard Model are divided into two families. But there's a third, rare kind — particles that, when swapped, don't just exchange places but tie themselves into a knot, remembering the intertwining rather than the path.

Ordinary wires: electrons jostle, lose energy, and heat up: that's resistance. In superconductors, some electrons pair up in sync, like dancers swirling without collisions. But these pairs hide: you can't see them directly, only infer their presence from flawless coordination.

A quantum computer is like an exquisite dish. There are recipes for ordinary kitchens, but special quantum states are secret ingredients that turn the dish into a masterpiece. One of them is 'magic'. The term was coined by John Preskill in 2018.

In the 1930s, Fritz Zwicky, observing the Coma cluster, noticed anomalously high galaxy velocities: their motion pointed to a huge hidden mass gravitationally binding the system.

A superconducting circuit is like a frictionless swing, only possible at temperatures of liquid helium (–273 °C). In such cold, electric current runs in a loop without fading, keeping its rhythm.

In the TiSe2 crystal, electrons behave like compass needles that suddenly start pointing in the same direction. This is called a nematic state — by analogy with liquid crystals, where molecules align along a common direction even though the material itself remains liquid.

Graphene is a sheet of carbon just one atom thick. Fold it in a special pattern and you get a new material — grokken. It wasn't a human who found it, but an AI: a large language model sifted through possibilities and proposed exactly this lattice.

A thin sheet of carbon, resembling an intricate mesh of triangles, hexagons, and octagons, lies on a substrate. By itself, it is not superconducting: electrons move through it haphazardly, bumping into atoms. But stretch the sheet evenly, like canvas on a frame, and the picture changes.

A superconductor crystal is squeezed in a small cell, like clamping it in a vise, but with water to distribute the pressure evenly. Pressure up to 1.08 GPa (about a hundred times greater than in a car tire) barely changes the temperature at which the material loses resistance.

In the crystal La₂₋ₓSrₓCuO₄, at a certain composition, two states coexist: superconductivity, where electrons move without loss, and a charge-density wave — a periodic bunching of electron density. These states compete for the same electron clouds, which resemble cross-shaped petals.

At a temperature of 4.3 degrees above absolute zero, a crystal of palladium telluride stops resisting electric current. Electrons pair up and move without loss, like a crowd holding hands. But this superconductor seems to have not one but two different ways of pairing.

A quantum computer is like an orchestra that can only perform in complete silence. The slightest noise, and the delicate melody falls apart. For quantum devices, heat is that noise: even faint infrared radiation from nearby components heats up the qubits and erases their quantum states.

Ordinary computer memory constantly consumes energy to avoid forgetting what's stored. A superconductor could store data without loss, but it's hard to make it switch. In the new work, a superconductor is sandwiched between two magnetic insulators.

In a conventional superconductor, electrons team up into pairs that stay put: their total momentum is zero. But sometimes it's different: pairs gain a shared momentum and start moving, like a school of fish swimming against the current. This state is called a pair density wave, and it's very finicky: it needs special conditions.

Empty space is never truly still. It teems with tiny energy fluctuations, like a sculptor's raw clay. In a new experiment, a thin film of superconducting material was placed inside a cavity designed to trap terahertz light, a form of invisible radiation. The cavity acted as a mold, shaping the vacuum fluctuations around the film.

An ordinary magnetic compass freezes when lightning strikes nearby. A sudden jump in the magnetic field throws the needle off. A similar problem has been hindering scientists trying to measure magnetism in strong pulsed fields: those that switch on for a thousandth of a second. The new setup tackles this with a laser beam.

A laser beam, like a fine chisel, burns oxygen out of a superconducting film. Where oxygen becomes scarce, the material stops conducting electricity without resistance. The researchers used this trick to draw patterns on the film that alter its properties.

A magnetic field is invisible, but you can make it 'glow'. To do that, take a tiny diamond with defects — places where a carbon atom is replaced by nitrogen and a neighboring lattice site is vacant. These defects, like sensitive compass needles, respond to the slightest changes in the magnetic field and emit light of varying brightness.

In NaAlSi, as it cools, electrons form fleeting ripples — stripes that appear and vanish, like patterns on water stirred by wind. These stripes intertwine with superconductivity, a state where current flows without resistance. Typically, for this, electrons pair up with uniform binding energy.

Electrons in a metal are like a crowd in a subway: each on their own, but at the slightest push, everyone moves at once. Physicists call this collective oscillation of the electron gas a plasmon. In superconductors, these oscillations are especially important because they reveal how electrons interact with each other.

A superconductor is like a city where electrons stop jostling and start moving in pairs, like people strolling arm in arm. In neodymium-strontium nickelate (Nd₀.₈Sr₀.₂NiO₂), this 'parade' kicks in at around 10 kelvin (minus 263 degrees Celsius), but not uniformly.

The crystal of RbMn6Bi5 resembles a five-story building of manganese atoms, where the residents on each floor form a pentagon. At room temperature, the magnetic moments of the atoms fluctuate chaotically, like compass needles during a magnetic storm.

The classic BCS theory of superconductivity, developed by John Bardeen, Leon Cooper, and Robert Schrieffer, describes the mechanism by which electrons pair up into Cooper pairs and move without resistance.

The NbSe2 crystal is like a stack of paper: layers lie tightly packed, and their properties blend together. Chemists found a way to pry this stack apart by nearly double — inserting long organic molecules between the layers like spacers. Now each layer behaves as if it were all alone, just one atom thick.

A superconducting single-photon detector is like a string stretched in the dark. When a single photon hits it, the string momentarily loses its superconductivity, and we hear a click. But until now, the string was always out of tune: the detector performed worse than the material would allow. The reason is the uneven distribution of current across the detector's width.

Superconductors are materials that conduct electricity without loss, but their properties are usually fixed. In the new work, scientists made a device resembling a crossroads of two superconducting tracks. By applying a weak magnetic field perpendicular to this crossroads, they were able to change the current the device can carry by a factor of four.

In a superconductor, electric current flows without loss, like water through a perfectly smooth pipe. But if you place such a material in a magnetic field, vortices appear inside — tiny whirlpools where superconductivity is destroyed. As long as these whirlpools stay put, current flows freely.

An ordinary superconductor works only in nature's freezer — at temperatures below minus one hundred degrees. The carbon-ball material K₃C₆₀ is no exception: without cold, it resists current like a crowd in a narrow corridor. But physicists noticed something strange: if you shine a laser on it, it starts conducting without loss even in warmth.

A superconductor is a material where electric current flows without loss, like water through a perfectly smooth pipe. But if vortices appear, the current starts to 'stumble' over these tiny whirlpools. In graphene twisted at a special angle, such vortices can be created and studied one by one.

A nanowire is like a tiny cable: inside is a magnetic core, outside is an aluminum shell that can conduct current without resistance. But they don't get along easily: a strong magnetic field destroys superconductivity, like noise drowns out a quiet melody.

A regular switch clicks, and current either flows or it doesn't. Now imagine a material that switches itself between 'conducts without loss' and 'resists' under the influence of a magnet. That's exactly the sandwich physicists built: a thin lead film on top of a superconductor made of bismuth, strontium, calcium, copper, and oxygen.

A superconducting qubit is a tiny electrical circuit that behaves like an artificial atom. In its normal state, current flows through it without resistance, and the energy levels are evenly spaced, like steps on a staircase. But if a single electron gets stuck in the circuit, everything changes.

In the crystal lattice of iron selenide, iron and selenium atoms alternate like bricks in a wall. But sometimes extra iron atoms sneak into the voids between them, like uninvited guests squeezing into the gaps between bricks.