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The bellow is colloquium schedule in Physics department. Every Wednesday 4:00 PM, colloquium is held in seminar room (Science Building III -201) Also, Free tea time will be held 30 minutes before colloquium stars. Please visit and enjoy the colloquium and tea time.


Colloquium 장소 및 시간: 세미나실(공학3동 201호) 오후 4시
연락처 : 물리학과 김기석교수 (279-2082), tkfkd@postech.ac.kr

          물리학과 사무실 김수경 (279-5971) skyung@postech.ac.kr

Engineering the Electronic Structure of Black Phosphorus

speaker : Prof. Keun Su Kim[POSTECH]

location :

date : 2015-10-7

There are rapidly growing interests in the study of two-dimensional (2D) atomic crystals owing to promising device characteristics that may impact our future electronics technology. A key issue is controlling their electronic states to overcome the limit of natural properties. Black phosphorus, consisting of 2D phosphorene layers, has been widely predicted to have a tunable band structure with external perturbations, such as strain and electric field. In this talk, I will introduce angle-resolved photoemission spectroscopy studies on the band evolution of black phosphorus by surface doping. The in-situ deposition of alkali-metal atoms induces 2D electron gas confined in few surface phosphorene layers. The vertical electric field from dopants modulates the band gap and tunes the material from a narrow-gap semiconductor to a band-overlapped semimetal. At the critical density of this semiconductor-semimetal transition, the system becomes a 2D Dirac semimetal whose band dispersion is highly anisotropic, linear in armchair and quadratic in zigzag directions.