Liquid Metal Electronic Structure, Theorized for 60 Years, Confirmed in Reality

Korean Researchers Achieve World's First Discovery
Helps Understand Mechanism of High-Temperature Superconductivity
Revolutionary Changes Expected if Room-Temperature Superconductivity Is Developed

The interface between a crystalline solid, in which the electronic structure of liquid metal was discovered, and liquid metal. Photo by Ministry of Science and ICT.

[Asia Economy Reporter Kim Bong-su] Korean physicists have succeeded in experimentally confirming the electronic structure of liquid metals predicted 60 years ago. Confirming the mechanism of high-temperature superconductivity could lead to groundbreaking changes such as lossless electrical transmission if room-temperature superconductivity is developed.

The Ministry of Science and ICT announced on the 5th that Professor Kim Geun-soo’s research team at Yonsei University experimentally confirmed the "electronic structure of liquid metals" predicted by the theoretical model proposed in the 1960s by Nobel Physics laureates Philip Anderson and Neville Mott.

While the electronic structure of crystalline solid metals with regular atomic arrangements can be relatively easily explained, liquid metals like mercury can freely change shape, making it very difficult to describe their electronic structure. Although the "electronic structure of liquid metals" was predicted by the theoretical model proposed by Philip Anderson and Neville Mott, Nobel laureates in Physics in 1960, it had never been experimentally observed in the past half-century.

Unlike previous methods that directly measured liquid metals, the research team succeeded in confirming the electronic structure of liquid metals through a unique method of spraying alkali metals onto a crystalline solid and observing the interface between them. Specifically, after spraying alkali metals (sodium, potassium, rubidium, cesium) onto the surface of a crystalline solid called black phosphorus (Heukrin), they measured the electronic structure of alkali-metal-doped black phosphorus using equipment. As a result, they discovered a uniquely backward-bending electronic structure and a "pseudogap" predicted by Anderson and Mott in 1960.

A pseudogap refers to a phenomenon where electrons have a complete energy gap due to quantum mechanical effects when atoms in a material are regularly arranged, but have an incomplete energy gap when atoms are irregularly arranged. In 1968, Neville Mott named this phenomenon the "pseudogap." Electrons in crystalline black phosphorus resonate and scatter due to the irregularly distributed alkali metal atoms, exhibiting characteristics similar to the "electronic structure of liquid metals."

By explaining the "pseudogap" through this research, it is expected to provide an important clue to understanding the unresolved mystery of high-temperature superconductivity in condensed matter physics. Furthermore, if the mechanism of high-temperature superconductivity is elucidated and room-temperature superconductivity is developed, lossless power transmission will become possible, bringing innovations to magnetic levitation trains, solutions to power supply shortages, and medical diagnostic devices such as MRI.

Professor Kim said, "The pseudogap can be explained by the collision effects with heteroatoms arranged irregularly," adding, "This will provide an important clue to understanding the high-temperature superconductivity phenomenon."