Terahertz conductivity of twisted bilayer graphene

• Main Authors: Castro Neto, A. H., Chia, Elbert E. M., Zou, Xingquan, Shang, Jingzhi, Leaw, Jianing, Luo, Zhiqiang, Luo, Liyan, Chan, La-o-vorakiat, Cheng, Liang, Cheong, Siew Ann, Su, Haibin, Zhu, Jian-Xin, Liu, Yanpeng, Loh, Kian Ping, Yu, Ting
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Science::Physics::Atomic physics
• Online Access: https://hdl.handle.net/10356/96399; http://hdl.handle.net/10220/9904
• Institution: Nanyang Technological University

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 ~2.7 THz. 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.