Ultrafast zero balance of the oscillator-strength sum rule in graphene

Jaeseok Kim, Seong Chu Lim, Seung Jin Chae, Inhee Maeng, Younghwan Choi, Soonyoung Cha, Young Hee Lee, Hyunyong Choi

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Oscillator-strength sum rule in light-induced transitions is one general form of quantum-mechanical identities. Although this sum rule is well established in equilibrium photo-physics, an experimental corroboration for the validation of the sum rule in a nonequilibrium regime has been a long-standing unexplored question. The simple band structure of graphene is an ideal system for investigating this question due to the linear Dirac-like energy dispersion. Here, we employed both ultrafast terahertz and optical spectroscopy to directly monitor the transient oscillator-strength balancing between quasi-free low-energy oscillators and high-energy Fermi-edge ones. Upon photo-excitation of hot Dirac fermions, we observed that the ultrafast depletion of high-energy oscillators precisely complements the increased terahertz absorption oscillators. Our results may provide an experimental priori to understand, for example, the intrinsic free-carrier dynamics to the high-energy photo-excitation, responsible for optoelectronic operation such as graphene-based phototransistor or solar-energy harvesting devices.

Original languageEnglish
Article number2663
JournalScientific reports
Volume3
DOIs
Publication statusPublished - 2013 Sep 23

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Terahertz Spectroscopy
Solar Energy
Physics
Light
Equipment and Supplies

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Cite this

Kim, J., Lim, S. C., Chae, S. J., Maeng, I., Choi, Y., Cha, S., ... Choi, H. (2013). Ultrafast zero balance of the oscillator-strength sum rule in graphene. Scientific reports, 3, [2663]. https://doi.org/10.1038/srep02663
Kim, Jaeseok ; Lim, Seong Chu ; Chae, Seung Jin ; Maeng, Inhee ; Choi, Younghwan ; Cha, Soonyoung ; Lee, Young Hee ; Choi, Hyunyong. / Ultrafast zero balance of the oscillator-strength sum rule in graphene. In: Scientific reports. 2013 ; Vol. 3.
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Kim, J, Lim, SC, Chae, SJ, Maeng, I, Choi, Y, Cha, S, Lee, YH & Choi, H 2013, 'Ultrafast zero balance of the oscillator-strength sum rule in graphene', Scientific reports, vol. 3, 2663. https://doi.org/10.1038/srep02663

Ultrafast zero balance of the oscillator-strength sum rule in graphene. / Kim, Jaeseok; Lim, Seong Chu; Chae, Seung Jin; Maeng, Inhee; Choi, Younghwan; Cha, Soonyoung; Lee, Young Hee; Choi, Hyunyong.

In: Scientific reports, Vol. 3, 2663, 23.09.2013.

Research output: Contribution to journalArticle

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