Researchers Expect For New Physical Properties Created By Entangled Electrons In Solids

Lecturer Yoichi Yamakawa, Associate Professor Seiichiro Ohnari, Professor Hiroshi Konya, Department of Physical Science, Graduate School of Science, Nagoya University, Tokai National University Organization, RIKEN Center for Emergent Matter Science Emergent Property Measurement Research Team Researcher Christopher J. Butler, Senior Researcher Yukio Kosaka (At the time of the research, Visiting Researcher of the Emergent Properties Research Team, Professor of the Graduate School of Science, Kyoto University), and an international joint research group led by Tetsuro Hanaguri, the sulfidation of barium and nickel We discovered that massless electrons (Dirac electrons [1] ) and electrons that behave like liquid crystals [2] coexist in the material BaNiS 2 . The results of this research are extremely rare electronic states, and can be expected as a platform for realizing completely new physical properties. In materials with special geometric symmetry [3] in the crystal structure or in which the electronic states are topologically [4] non-trivial [5] , the electron mass can be zero. On the other hand, non-trivial and useful phenomena such as high-temperature superconductivity [8] and various magnetisms are observed in transition metal compounds [7] with strong repulsive interactions between electrons (electron correlation [6] ). Research on materials based on symmetry and topology and research on electron correlation are two major trends in modern condensed matter physics. was difficult to do.


In this study, the international joint research group found that mass-less Dirac electrons coexist in BaNiS 2 with directional electrons generated by electron correlation, as in liquid crystals, using scanning tunneling microscopy/spectroscopy (STM). /STS) [9] and its theoretical analysis. This opens the door to exploring emergent phenomena that interweave symmetry/topology and electron correlation.
This research was published in the online version of the scientific journal Proceedings of the National Academy of Sciences of the United States of America (PNAS) (December 2nd).