“Pseudogap in surface-doped black phosphorus”

Dr. Keun Su Kim
Department of Physics, Yonsei University

Jun. 11 (Fri.), 04:00 PM
E6-2. 1st fl. #1323
https://kaist.zoom.us/j/89283252628
회의 ID: 892 8325 2628
암호: 916514

Abstract:
Many of the interesting quantum phenomena arise at the interface between a crystalline insulator and disordered dopants. In this kind of the interface between black phosphorus and alkali metals, we have studied the tunable band gap1, topological phase transition2, and the evolution of quantum phases (or pseudospin)3. After briefly summarizing the past results, I will introduce our recent discovery of a pseudogap in black phosphorus doped by various alkali metals4. With angle-resolved photoemission spectroscopy (ARPES), we reveal an anomalous band dispersion of back-bending and pseudogap, which can be explained by the Anderson-McMillan band dispersion of liquid metals developed in 1960s. This is a natural consequence of resonance scattering by dopant ions with only short-range order (or liquid order). The depth of a 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.

References
1. J. Kim et al., Science 349, 723 (2015)
2. J. Kim et al., Phys. Rev. Lett. 119, 226801 (2017)
3. S. W. Jung, S. H, Ryu, W. J. Shen et al., Nature Mater. 19, 277 (2020)
4. S. H. Ryu, M. Huh, D. Y. Park et al., Nature, accepted (2021)