[행사/세미나] [Seminar] Dec. 15(Thur.) Pseudogap and topological phase transition in black phosphorus
- 물리학과
- 조회수3126
- 2022-12-08
양자물질초전도연구실에서 연세대학교 김근수 교수님을 초청하여 아래와 같이 세미나를 개최합니다.
학과 구성원 여러분의 많은 참여를 부탁 드립니다.
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○ Topic: Pseudogap and topological phase transition in black phosphorus
○ Speaker: 김 근 수 교수님 (연세대학교)
○ Date/time: 2022. 12. 15. (Thur.) 16:30 PM
○ Place: 기초학문관 2층 51205호 강의실
○ Abstract: The tunable band structure of two-dimensional quantum mater is not only interesting in itself, but also useful for the fundamental study of condensed matter physics. As example, surface chemical doping can be used to modulate the band gap in black phosphorus over the energy range greater than its intrinsic band gap [1]. This could be used to deliberately induce the topological phase transition to a novel Dirac semimetal protected by spacetime inversion symmetry [2]. This could also be used to trace the evolution of quantum phases (pseudospin) order across the topological phase transition [3]. In this talk, I will introduce our recent study on band renormalizations and pseudogap in black phosphorus doped by alkali metals [4]. Using angle-resolved photoemission spectroscopy (ARPES), we found that the typical quadratic energy-momentum relation of doped black phosphorus anomalously bends back towards zero momentum, which can be accounted for by Anderson-McMillan’s theory developed for the band structure of liquid metals back in the 1960s. This is a natural consequence of resonance scattering by the potential of effectively ionized dopants with short-range order. The depth of scattering potential tuned by different kinds of alkali metal (Na, K, Rb, and Cs) allows us to classify the pseudogap of p-wave and d-wave resonance.