DGIST unveils discovery of a one third fractional quantum state

DGIST unveils discovery of a one third fractional quantum state
by Riko Seibo
Tokyo, Japan (SPX) Jan 22, 2025

Professor Youngwook Kim from the Department of Physics and Chemistry at the Daegu Gyeongbuk Institute of Science and Technology (DGIST) and Professor Gilyoung Cho from the Korea Advanced Institute of Science and Technology (KAIST) have uncovered a novel quantum state through their investigation of twisted graphene structures. This discovery could pave the way for advanced electronic devices and quantum memory technologies capable of handling complex computations.

Quantum physics plays a fundamental role in understanding how particles and atoms interact, forming the basis for technological innovations that manipulate nature at microscopic levels. This research is notable for identifying a new quantum state that is unattainable with conventional semiconductor technologies, thus broadening the horizon for future quantum advancements.

Graphene, a carbon-based material as thin as a sheet of paper, was the focus of this study. The researchers analyzed a structure of two graphene layers twisted slightly in relation to one another. This arrangement produces unique overlapping patterns, akin to two transparent films with regular designs rotated slightly. These new patterns were found to impose unique rules on electron movement, restricting their transition between layers and creating significant Coulomb interactions.

The most remarkable finding was the identification of a "1/3 fractional quantum Hall state," where electrons behave as if divided into three parts. This phenomenon arises from strong electron interactions across the layers. Monte Carlo simulations confirmed the theoretical basis and physical implications of this state.

Professor Gilyoung Cho from KAIST commented, "Our discovery of a fractional quantum Hall state in new materials could contribute significantly to the development of quantum computer technologies."

Professor Youngwook Kim of DGIST added, "This study is the result of close international collaboration with NIMS in Japan and the Max Planck Society for the Advancement of Science in Germany. Utilizing the high-magnetic-field experimental equipment of the Max Planck Society was crucial to our findings. Moving forward, we aim to replicate these conditions in a non-magnetic environment."

The research, led by Professor Youngwook Kim and PhD student Seyoung Jin from POSTECH, has been published in the journal Nature Communications. Funding was provided by the National Research Foundation of Korea, the Samsung Future Technology Development Foundation, and the Institute for Basic Science.

Research Report:Observation of 1/3 fractional quantum Hall physics in balanced large angle twisted bilayer graphene