Ultrafast unbalanced electron distributions in quasicrystalline 30° twisted bilayer graphene

Takeshi Suzuki, Takushi Iimori, Sung Joon Ahn, Yuhao Zhao, Mari Watanabe, Jiadi Xu, Masami Fujisawa, Teruto Kanai, Nobuhisa Ishii, Jiro Itatani, Kento Suwa, Hirokazu Fukidome, Satoru Tanaka, Joung Real Ahn, Kozo Okazaki, Shik Shin, Fumio Komori, Iwao Matsuda

Research output: Contribution to journalArticle

Abstract

Ultrafast carrier dynamics in a graphene system are very important in terms of optoelectronic devices. Recently, a twisted bilayer graphene has been discovered that possesses interesting electronic properties owing to strong modifications in interlayer couplings. Thus, a better understanding of ultrafast carrier dynamics in a twisted bilayer graphene is highly desired. Here, we reveal the unbalanced electron distributions in a quasicrystalline 30° twisted bilayer graphene (QCTBG), using time- A nd angle-resolved photoemission spectroscopy on the femtosecond time scale. We distinguish time-dependent electronic behavior between the upper- A nd lower-layer Dirac cones and gain insight into the dynamical properties of replica bands, which show characteristic signatures due to Umklapp scatterings. The experimental results are reproduced by solving a set of rate equations among the graphene layers and substrate. We find that the substrate buffer layer plays a key role in initial carrier injections to the upper and lower layers. Our results demonstrate that QCTBG can be a promising element for future devices.

Original languageEnglish
Pages (from-to)11981-11987
Number of pages7
JournalACS nano
Volume13
Issue number10
DOIs
Publication statusPublished - Oct 22 2019

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Graphite
electron distribution
Graphene
graphene
Electrons
carrier injection
Substrates
Buffer layers
Photoelectron spectroscopy
optoelectronic devices
replicas
electronics
Electronic properties
Optoelectronic devices
Cones
interlayers
cones
photoelectric emission
buffers
signatures

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Suzuki, T., Iimori, T., Ahn, S. J., Zhao, Y., Watanabe, M., Xu, J., ... Matsuda, I. (2019). Ultrafast unbalanced electron distributions in quasicrystalline 30° twisted bilayer graphene. ACS nano, 13(10), 11981-11987. https://doi.org/10.1021/acsnano.9b06091

Ultrafast unbalanced electron distributions in quasicrystalline 30° twisted bilayer graphene. / Suzuki, Takeshi; Iimori, Takushi; Ahn, Sung Joon; Zhao, Yuhao; Watanabe, Mari; Xu, Jiadi; Fujisawa, Masami; Kanai, Teruto; Ishii, Nobuhisa; Itatani, Jiro; Suwa, Kento; Fukidome, Hirokazu; Tanaka, Satoru; Ahn, Joung Real; Okazaki, Kozo; Shin, Shik; Komori, Fumio; Matsuda, Iwao.

In: ACS nano, Vol. 13, No. 10, 22.10.2019, p. 11981-11987.

Research output: Contribution to journalArticle

Suzuki, T, Iimori, T, Ahn, SJ, Zhao, Y, Watanabe, M, Xu, J, Fujisawa, M, Kanai, T, Ishii, N, Itatani, J, Suwa, K, Fukidome, H, Tanaka, S, Ahn, JR, Okazaki, K, Shin, S, Komori, F & Matsuda, I 2019, 'Ultrafast unbalanced electron distributions in quasicrystalline 30° twisted bilayer graphene', ACS nano, vol. 13, no. 10, pp. 11981-11987. https://doi.org/10.1021/acsnano.9b06091
Suzuki T, Iimori T, Ahn SJ, Zhao Y, Watanabe M, Xu J et al. Ultrafast unbalanced electron distributions in quasicrystalline 30° twisted bilayer graphene. ACS nano. 2019 Oct 22;13(10):11981-11987. https://doi.org/10.1021/acsnano.9b06091
Suzuki, Takeshi ; Iimori, Takushi ; Ahn, Sung Joon ; Zhao, Yuhao ; Watanabe, Mari ; Xu, Jiadi ; Fujisawa, Masami ; Kanai, Teruto ; Ishii, Nobuhisa ; Itatani, Jiro ; Suwa, Kento ; Fukidome, Hirokazu ; Tanaka, Satoru ; Ahn, Joung Real ; Okazaki, Kozo ; Shin, Shik ; Komori, Fumio ; Matsuda, Iwao. / Ultrafast unbalanced electron distributions in quasicrystalline 30° twisted bilayer graphene. In: ACS nano. 2019 ; Vol. 13, No. 10. pp. 11981-11987.
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