물리학과

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물리학과입니다.

This subject has been actively studied for decades, aiming to develop next-generation novel applications. Also, the insulator-metal transition is a central concept in condensed matter physics as it is closely related to various important phenomena, ranging from high-temperature superconductivity, colossal magnetoresistance, to insulating states in Van der Waals materials more recently.
Thus, it is significant in finding the actual material that shows the electronic transition without a structural and magnetic transition, by understanding electronic phases and their transitions via insulator-metal transitions. However, to our knowledge, the originally-proposed electronic transition in theory by Mott in 1949 is not clearly confirmed in any real solids yet.
Here, we present such experimental evidence. Via comprehensive x-ray diffraction, resistivity, magnetic susceptibility, heat capacity, Raman scattering, and muon spin relaxation measurements on NiS(2-x)Se(x), we map out an accurate phase diagram based on the real Se doping to date. Key experimental findings are well reproduced by our dynamical mean-field theory calculations, providing comprehensive microscopic understandings of the competing electronic and magnetic phases and their transitions. Our results provide a crystal clear model for the pure Mott transition in crystalline arrays with theoretical explanations, which could facilitate a novel application, such as ultra-fast switching electronic devices in the future.