A team of South Korean scientists led by physicist Seok-bae Lee recently sent shockwaves through the scientific community by announcing the discovery of the first room temperature superconductor. But the research paper has been both praised and pilloried by a scientific community eager to independently test its findings.

In two preprint papers posted on arXiv, Lee and colleagues at the Quantum Energy Research Institute introduced LK-99, a material they say exhibits superconductivity at temperatures up to 400K (127°C), greatly exceeding the previous record of -135°C. If validated, this purported breakthrough could enable quantum computers, lossless power transmission, and revolutionary battery storage technology.

What is a superconductor?

The temperature of a substance is a measure of the kinetic energy of the molecules within. A hot material means its electrons are moving around like crazy, whereas cold represents slower, quieter electrons. A superconductor allows electrons to flow with zero resistance—generating zero heat.

When a substance is cooled below its critical temperature, electrons can glide about, like a person crossing a nearly empty room where only a few people are doing yoga. In contrast, in warmer temperatures, electrons in the material collide and repel each other, like people trying to cross through a crowded disco dance floor. This resistance means the loss of power or energy.

These scientists have effectively claimed to have developed a way to make crossing the crowded dance floor as easy as crossing a cold and empty yoga room.

What’s so special about LK-99?

Using a novel solid-state reaction method summarized in the paper, the researchers synthesized LK-99 and tested its electrical resistance. That resistance dropped sharply at 220°C, indicative of superconductivity. They also demonstrated partial magnetic levitation, a hallmark property—called the "Meissner effect"—of superconductors.

Skeptics have claimed that the the partial magnetic levitation illustrated in the paper is just an illusion generated by another magnet that’s outside the frame of the image, pointing to the fact that the object isn’t fully levitating. The researchers say the partial levitation is due to imperfections in the LK-99 material, where parts of the substance are in a superconductive state while other parts are not.

The sparse details provided about the experimental conditions are a key point of contention. There have been prior claims of achieving room-temperature superconductivity that were subsequently discredited. Science magazine reports that other researchers are now racing to independently reproduce LK-99.