“Kondo cloud condensation in a highly-doped semiconductor metal”

Dr. Hyunsik Im
Department of Physics and Semiconductor Science,
Dongguk University

Nov. 18 (Fri.), 02:30 PM
E6-2. 1st fl. #1323
https://kaist.zoom.us/j/89378880769

회의 ID: 893 7888 0769
암호: 909660

Abstract:
When a magnetic moment is embedded in a metal, it captures itinerant electrons to form the Kondo cloud with a size of a few micrometres. For a metal with dense magnetic impurities such that Kondo clouds overlap with each other, correlated ground states are formed. Here, we study this issue by performing electrical transport and tunneling DOS spectroscopy measurements in a crystalline silicon metal where localized magnetic moments exist. We detect the Kondo effect in the resistivity of the Si metal and an exotic BCS-like pseudogap in the DOS near the Fermi energy. The BCS-like DOS structure is tuned by applying an external magnetic field and transformed into a paramagnetic Coulomb gap. This phenomenon is interpreted as the formation of a correlated ground state of overlapping Kondo clouds (Kondo condensation). Our experimental findings demonstrate the observation of the magnetic version of BCS pair condensation and will be useful for understanding complex Kondo systems.