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Informal CMTC Seminar

Fri, Nov 1, 2019 11:00 am - 12:00 pm
4402 Atlantic Building


Title: Moiré laboratory of rescaled solids: graphene and transition metal dichalcogenide systems

Speaker: Noah Fanqi Yuan (MIT)

Abstract: A moiré superlattice is formed by two similar lattices but with small lattice mismatch. Recently, exciting experimental results are reported in moiré superlattices of graphene [1, 2] and transition metal dichalcogenide (TMD) [3, 4]. In this talk, I would like to discuss our theoretical understanding of such moiré systems. The take-home message is that, compared with atomic lattices, moiré superlattices can be regarded as rescaled solids with similar “chemistry”, but tunable band structure and interaction strength on the energy scale of 10~100 meV. The interplay between such “moiré chemistry” and Coulomb interactions lead to various correlated phases, which may help us to understand graphene [5, 6, 7] and TMD superlattices [8, 9, 10]. If I have time, weak coupling approach in momentum space [11, 12, 13] will also be discussed.

[1] Y. Cao, V. Fatemi, A. Demir, S. Fang, S. L. Tomarken, J. Y. Luo, J. D. Sanchez-Yamagishi, K. Watanabe, T. Taniguchi, E. Kaxiras, et al., Nature 556, 80 (2018).

[2] Y. Cao, V. Fatemi, S. Fang, K. Watanabe, T. Taniguchi, E. Kaxiras, and P. Jarillo-Herrero, Nature 556, 43 (2018).

[3] Yanhao Tang, Lizhong Li, Tingxin Li, Yang Xu, Song Liu, Katayun Barmak, Kenji Watanabe, Takashi Taniguchi, Allan H MacDonald, Jie Shan, Kin Fai Mak, arXiv: 1910.08673 (2019).

[4] Emma C. Regan, Danqing Wang, Chenhao Jin, M. Iqbal Bakti Utama, Beini Gao, Xin Wei, Sihan Zhao, Wenyu Zhao, Kentaro Yumigeta, Mark Blei, Johan Carlstroem, Kenji Watanabe, Takashi Taniguchi, Sefaattin Tongay, Michael Crommie, Alex Zettl, Feng Wang, arXiv: 1910.09047 (2019).

[5] N. F. Q. Yuan and L. Fu, Phys. Rev. B 98, 045103 (2018).

[6] M. Koshino, N. F. Q. Yuan, T. Koretsune, M. Ochi, K. Kuroki, and L. Fu, Phys. Rev. X 8, 031087 (2018).

[7] H. Isobe, N. F. Q. Yuan, and L. Fu, Phys. Rev. X 8, 041041 (2018).

[8] F.Wu, T. Lovorn, E. Tutuc, and A. H. MacDonald, Phys. Rev. Lett. 121, 026402 (2018).

[9] F. Wu, T. Lovorn, E. Tutuc, I. Martin, and A. MacDonald, Phys. Rev. Lett. 122, 086402 (2019).

[10] Yang Zhang*, Noah F. Q. Yuan*, and Liang Fu, to appear on arXiv.

[11] Noah F. Q. Yuan, Hiroki Isobe, Liang Fu, arXiv:1901.05432 (2019), to appear on Nature Communications.

[12] Noah F. Q. Yuan, Liang Fu, arXiv:1910.10179 (2019).

[13] Anirudh Chandrasekaran, Alex Shtyk, Joseph J. Betouras, and Claudio Chamon, arXiv:1910.10183 (2019).

Condensed Matter Theory Center website:

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