Terahertz Conductivity of Twisted Bilayer Graphene

Xingquan Zou, Jingzhi Shang, Jianing Leaw, Zhiqiang Luo, Liyan Luo, Chan La-o-vorakiat, Liang Cheng, S. A. Cheong, Haibin Su, Jian-Xin Zhu, Yanpeng Liu, Kian Ping Loh, A. H. Castro Neto, Ting Yu, and Elbert E. M. Chia
Phys. Rev. Lett. 110, 067401 – Published 7 February 2013
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Abstract

Using terahertz time-domain spectroscopy, the real part of optical conductivity [σ1(ω)] of twisted bilayer graphene was obtained at different temperatures (10–300 K) in the frequency range 0.3–3 THz. On top of a Drude-like response, we see a strong peak in σ1(ω) at 2.7THz. We analyze the overall Drude-like response using a disorder-dependent (unitary scattering) model, then attribute the peak at 2.7 THz to an enhanced density of states at that energy, which is caused by the presence of a van Hove singularity arising from a commensurate twisting of the two graphene layers.

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  • Received 9 April 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.067401

© 2013 American Physical Society

Authors & Affiliations

Xingquan Zou1, Jingzhi Shang1, Jianing Leaw1, Zhiqiang Luo1, Liyan Luo1, Chan La-o-vorakiat1, Liang Cheng1, S. A. Cheong1, Haibin Su2, Jian-Xin Zhu3, Yanpeng Liu4, Kian Ping Loh4, A. H. Castro Neto5, Ting Yu1, and Elbert E. M. Chia1

  • 1Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore
  • 2Division of Materials Science, School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore
  • 3Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
  • 4Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore
  • 5Graphene Research Centre and Physics Department, National University of Singapore, 6 Science Drive 2, 117546 Singapore

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Issue

Vol. 110, Iss. 6 — 8 February 2013

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