Salvato in:
| Autori principali: | , , , , , |
|---|---|
| Natura: | Preprint |
| Pubblicazione: |
2025
|
| Soggetti: | |
| Accesso online: | https://arxiv.org/abs/2502.03558 |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1866913680997744640 |
|---|---|
| author | Silva, Rodrigo Becerra Huang, Jay Wang, Bob Minyu Song, Ziyi Travaglini, Henry Clark Yu, Dong |
| author_facet | Silva, Rodrigo Becerra Huang, Jay Wang, Bob Minyu Song, Ziyi Travaglini, Henry Clark Yu, Dong |
| contents | Understanding the ultrafast dynamics and transport of photoexcited carriers in topological insulators is crucial for the optical manipulation of spins and may shed light on the nature of topological excitons. Here we investigate bulk-insulating Sb-doped $\mathrm{Bi_2Se_3}$ nanoribbons via ultrafast transient photovoltage microscopy. The probe-pulse-induced photovoltage is substantially suppressed by a pump pulse. Recovery time increases from 50 to 1600 picoseconds as the pump fluence increases. We found that the diffusivity of photoexcited carriers increases significantly at lower carrier concentrations, up to 800 cm$^2$/s at 21 K, two to three orders of magnitude higher than that of band-edge carriers. Remarkably, the photoexcited carriers travel up to 10 $μ$m for hundreds of picoseconds at this high diffusivity. The diffusivity peaks in intrinsic devices and is reduced at high temperatures. We discuss the possible mechanisms of long-ranged super-diffusion in the frames of hot carriers and exciton condensation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_03558 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Super-diffusion of Photoexcited Carriers in Topological Insulator Nanoribbons Silva, Rodrigo Becerra Huang, Jay Wang, Bob Minyu Song, Ziyi Travaglini, Henry Clark Yu, Dong Mesoscale and Nanoscale Physics Understanding the ultrafast dynamics and transport of photoexcited carriers in topological insulators is crucial for the optical manipulation of spins and may shed light on the nature of topological excitons. Here we investigate bulk-insulating Sb-doped $\mathrm{Bi_2Se_3}$ nanoribbons via ultrafast transient photovoltage microscopy. The probe-pulse-induced photovoltage is substantially suppressed by a pump pulse. Recovery time increases from 50 to 1600 picoseconds as the pump fluence increases. We found that the diffusivity of photoexcited carriers increases significantly at lower carrier concentrations, up to 800 cm$^2$/s at 21 K, two to three orders of magnitude higher than that of band-edge carriers. Remarkably, the photoexcited carriers travel up to 10 $μ$m for hundreds of picoseconds at this high diffusivity. The diffusivity peaks in intrinsic devices and is reduced at high temperatures. We discuss the possible mechanisms of long-ranged super-diffusion in the frames of hot carriers and exciton condensation. |
| title | Super-diffusion of Photoexcited Carriers in Topological Insulator Nanoribbons |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2502.03558 |