Cascade of electronic transitions in magic-angle twisted bilayer graphene

Nature
Dillon WongAli Yazdani

Abstract

Magic-angle twisted bilayer graphene exhibits a variety of electronic states, including correlated insulators1-3, superconductors2-4 and topological phases3,5,6. Understanding the microscopic mechanisms responsible for these phases requires determination of the interplay between electron-electron interactions and quantum degeneracy (the latter is due to spin and valley degrees of freedom). Signatures of strong electron-electron correlations have been observed at partial fillings of the flat electronic bands in recent spectroscopic measurements7-10, and transport experiments have shown changes in the Landau level degeneracy at fillings corresponding to an integer number of electrons per moiré unit cell2-4. However, the interplay between interaction effects and the degeneracy of the system is currently unclear. Here we report a cascade of transitions in the spectroscopic properties of magic-angle twisted bilayer graphene as a function of electron filling, determined using high-resolution scanning tunnelling microscopy. We find distinct changes in the chemical potential and a rearrangement of the low-energy excitations at each integer filling of the moiré flat bands. These spectroscopic features are a direct consequence of Coulomb...Continue Reading

References

Jul 7, 2011·Proceedings of the National Academy of Sciences of the United States of America·Rafi Bistritzer, Allan H MacDonald
Aug 3, 2011·The Review of Scientific Instruments·Guohong LiEva Y Andrei
Feb 10, 2016·Nano Letters·Kyounghwan KimEmanuel Tutuc
Mar 8, 2018·Nature·Yuan CaoPablo Jarillo-Herrero
Jan 27, 2019·Science·Matthew YankowitzCory R Dean
Jul 20, 2019·Physical Review Letters·Jian Kang, Oskar Vafek
Jul 28, 2019·Science·Aaron L SharpeDavid Goldhaber-Gordon
Aug 2, 2019·Nature·Alexander KerelskyAbhay N Pasupathy
Mar 3, 2020·The Review of Scientific Instruments·Dillon WongAli Yazdani
Mar 7, 2020·Physical Review Letters·Yuan CaoPablo Jarillo-Herrero
Mar 24, 2020·Physical Review Letters·Ming Xie, A H MacDonald
May 10, 2020·Physical Review Letters·Nick BultinckMichael P Zaletel

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Citations

Jul 17, 2020·Nature·Harpreet Singh AroraStevan Nadj-Perge
Nov 11, 2020·Proceedings of the National Academy of Sciences of the United States of America·Maine ChristosMathias S Scheurer
Jan 20, 2021·Nature·Youngjoon ChoiStevan Nadj-Perge
Nov 20, 2020·Nature Materials·Eva Y Andrei, Allan H MacDonald
Feb 3, 2021·Nature·Jeong Min ParkPablo Jarillo-Herrero
Mar 13, 2021·Science·Ali Yazdani
Mar 27, 2021·Advanced Materials·Dong QiuJie Xiong
Apr 2, 2021·Nature·Jeong Min ParkPablo Jarillo-Herrero
Apr 9, 2021·Nature·Yu SaitoAndrea F Young
May 6, 2021·Nature Communications·Canxun ZhangMichael F Crommie
May 7, 2021·Science Advances·Eslam KhalafAshvin Vishwanath
May 14, 2021·Nature Communications·Xiaomeng LiuAli Yazdani
Jul 23, 2021·Nature·Yuan CaoPablo Jarillo-Herrero
Jul 9, 2021·Nature Communications·Nikhil TilakEva Y Andrei
Sep 18, 2021·Nature Communications·Bin-Bin ChenZi Yang Meng
Nov 2, 2021·Advanced Science·Mengya LiuGui Yu

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Methods Mentioned

BETA
scanning tunnelling microscopy

Software Mentioned

MATBG

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