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Research Team Led by Hyunsik Lim and Hyungsang..

Date 2023.03.17. Writer 최수완 Hits 680

Research Team Led by Hyunsik Lim and Hyungsang Kim, Professors at Dongguk University, Discovers a New Quantum Material via Spin Cloud Condensation

왼쪽 임현식 교수, 오른쪽 김형상 교수

Left: Professor, Hyunsik Lim; Right: Professor, Hyungsang Kim

 

- Successful discovery of a new Bose–Einstein condensate (Published in Nature Physics)

 

○ A research team led by Hyunsik Lim, Professor of Physics and Semi-conductor Science at Dongguk University, has discovered and analyzed a new quantum material using the condensates of spin clouds in an ultracold silicon metal.

* Spin cloud (also known as a “Kondo cloud”): Free electrons formed to screen the magneticity of a metal or semi-conductor

 ※ Co-corresponding authors: Professor Eunkyu Kim, Professor Sangjin Shin (Hanyang University), Professor Yeonwook Jung (Sungkyunkwan University)

 

Spin clouds play a major role in high-temperature superconductivity. Due to their vanishing resistance, spin clouds enable applications such as levitation trains (maglev) and magnetic resonance imaging (MRI).

 

Despite the theoretical and experimental interest, the study of new quantum materials formed by spin clouds and their interactions in the field of condensed matter physics face many unresolved challenges.

 

While researching quantum computer components, a research team led by Professors Hyunsik Lim and Hyungsang Kim from Dongguk University inadvertently discovered an unusual signal in silicon metal. Upon initial investigation, they suspected it was not an error from the component or measurement device but instead a new quantum mechanical model.

 

Although they faced significant experimental challenges such as the need to measure ultracold temperatures and overcome interpretation problems, which made preceding research on spin clouds extremely difficult, the research team has persisted in their effort since 2015.

 

The team used spectroscopic and electrical conductivity measurements to determine that the observed signal in the silicon metal derived from a new material that exhibited the characteristics of the Bose–Einstein condensate, which is a phase of material discovered in 1990 that follows the solid, liquid, gas, and plasma phases.

 

The research team successfully discovered and elucidated, for the first time in the world, that a new quantum material can be formed by condensing ultracold spin clouds (1[K], -272.15[℃]) using silicon metal.

 

The discovery is expected to contribute to a greater understanding of spin–spin interactions in metals and semiconductors as well as the study of strongly correlated materials, including high-temperature superconductors.

 * Strongly correlated material: a material that exhibits unusual phenomena not seen in typical conductors and insulators due to the strong interactions between its constituent particles.

 

Professor Lim stated, “If we can create and control another quantum condensed state through this research, it can be applied to quantum device technology.” He added, “Understanding the properties of various spin clouds in response to changes in the concentration of spin clouds in pure metals through follow-up research is important.”

 

The team’s research was supported by the Basic Research Program (mid-career and basic laboratory) of the Ministry of Science and ICT. An article describing their achievement was published* in the international academic journal Nature Physics on February 7 (16:00 GMT, February 6 local time).

 * Title of the paper: Observation of Kondo condensation in a degenerately doped silicon metal