1. Prolonged photo-carriers generated in a massive-and-anisotropic Dirac material
- Author
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Kazuki Sumida, Yoshifumi Ueda, Akio Kimura, Yuichi Akahama, Masashi Nakatake, Shik Shin, Munisa Nurmamat, Siyuan Zhu, Ryohei Yori, Masaki Taniguchi, and Yukiaki Ishida
- Subjects
Materials science ,Photoemission spectroscopy ,Dirac (software) ,lcsh:Medicine ,FOS: Physical sciences ,02 engineering and technology ,Electronic structure ,01 natural sciences ,symbols.namesake ,Condensed Matter::Materials Science ,0103 physical sciences ,010306 general physics ,Anisotropy ,lcsh:Science ,Condensed Matter - Materials Science ,Multidisciplinary ,Condensed matter physics ,business.industry ,Condensation ,Fermi level ,lcsh:R ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Semiconductor ,symbols ,Direct and indirect band gaps ,lcsh:Q ,0210 nano-technology ,business - Abstract
Transient electron-hole pairs generated in semiconductors can exhibit unconventional excitonic condensation. Anisotropy in the carrier mass is considered as the key to elongate the life time of the pairs, and hence to stabilize the condensation. Here we employ time- and angle-resolved photoemission spectroscopy to explore the dynamics of photo-generated carriers in black phosphorus. The electronic structure above the Fermi level has been successfully observed, and a massive-and-anisotropic Dirac-type dispersions are confirmed; more importantly, we directly observe that the photo-carriers generated across the direct band gap have the life time exceeding 400 ps. Our finding confirms that black phosphorus is a suitable platform for excitonic condensations, and also open an avenue for future applications in broadband mid-infrared BP-based optoelectronic devices., Comment: 13 pages, 5 figures
- Published
- 2018
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