Emerging New Quantum Phases in GaTa4Se8 under pressure
일 시 : 2021년 08월 12일 목요일 16:00
연 사 : 한 명 준 교수 (KAIST 물리학과)
장 소 : 온라인 진행 ( https://us02web.zoom.us/j/86124916947?pwd=dXZpb0ltV2dNZ3JVYlZnekJNZkVVZz09)
HOST : 신 상 진 교수님
초 록
GaTa4Se8 is the first confirmed real-material example that carries the novel Jeff=3/2 moment [1, 2]. While this exotic magnetic ground state is shown to exist in the Mott phase at ambient pressure, the key remaining question is about its fate under pressure since this material exhibits the insulator-to-metal transition followed by superconducting transition as a function of pressure. In this talk, I will report our recent progress on this issue. First, under moderate pressure, we found, Jeff=3/2 moment is well maintained in the metallic regime [3]. Our DFT+DMFT (density functional theory + dynamical mean-field theory) calculation and RIXS (resonant inelastic x-ray scattering) experiment coincidentally indicate that the metallic phase of this material is still well identified by Jeff=3/2 state. This result can indicate the intriguing possibility regarding the origin of superconductivity appearing at higher pressure, which will be discussed in the second part [4, 5]. Finally, I will present and discuss the discovery of new phases at the very high pressure that has not been reached before in this material [6]. The extended pressure phase diagram will be presented.