Nonlinear terahertz field-induced carrier dynamics in photoexcited epitaxial monolayer graphene

Hassan A. Hafez, Ibraheem Al-Naib, Marc M. Dignam, Yoshiaki Sekine, Katsuya Oguri, François Blanchard, David G. Cooke, Satoru Tanaka, Fumio Komori, Hiroki Hibino, Tsuneyuki Ozaki

研究成果: Contribution to journalArticle査読

55 被引用数 (Scopus)

抄録

We report nonlinear terahertz (THz) field transmission through photoexcited monolayer epitaxial graphene via differential transmission measurements enabled by optical-pump/intense-terahertz-probe (OPITP) spectroscopy. After photoexcitation of graphene, a transmission enhancement, defined by a positive differential transmission of the intense terahertz probe pulse, is observed. This is due to suppression of the graphene photoconductivity arising from an increased carrier scattering rate due to the increase in the carrier density and the extra energy from the photoexcited hot carriers. Thus, the transient enhancement in transmission increases as the optical pump fluence increased. Most interestingly, we observe that the transmission enhancement after photoexcitation decreases as the THz field strength is increased, which we attribute to the combined effects of the intense THz electric field and the optical pump fluence on the carrier scattering rate. We model the carrier dynamics in the graphene using the length gauge interaction Hamiltonian with the inclusion of short-range scattering by neutral impurities and the interaction of the carriers with optical phonons. Comparing the experimental and simulated transmission results, we extract the nonequilibrium effective lattice temperature of graphene as a function of the optical pump fluence and THz field strength.

本文言語英語
論文番号035422
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
91
3
DOI
出版ステータス出版済み - 1 16 2015

All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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