Spectroscopy of Twisted Bilayer Graphene Correlated Insulators

被引：29
作者：
Calugaru, Dumitru [1 ]
Regnault, Nicolas [1 ]
Oh, Myungchul [1 ]
Nuckolls, Kevin P. [1 ]
Wong, Dillon [1 ]
Lee, Ryan L. [1 ]
Yazdani, Ali [1 ]
Vafek, Oskar [2 ,3 ]
Bernevig, B. Andrei [1 ,4 ,5 ]
机构：
[1] Princeton Univ, Dept Phys, Princeton, NJ 08544 USA
[2] Natl High Magnet Field Lab, Tallahassee, FL 32310 USA
[3] Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA
[4] Donostia Int Phys Ctr, P Manuel de Lardizabal 4, Donostia San Sebastian 20018, Spain
[5] Basque Fdn Sci, IKERBASQUE, Bilbao 48009, Spain
来源：
PHYSICAL REVIEW LETTERS | 2022年 / 129卷 / 11期
基金：
欧洲研究理事会; 美国国家科学基金会;
关键词：
MAGIC-ANGLE; BROKEN-SYMMETRY; MOIRE; ORDERS;
D O I：
10.1103/PhysRevLett.129.117602
中图分类号：
O4 [物理学];
学科分类号：
0702 ;
摘要：
We analytically compute the scanning tunneling microscopy (STM) signatures of integer-filled correlated ground states of the magic angle twisted bilayer graphene (TBG) narrow bands. After experimentally validating the strong-coupling approach at +/- 4 electrons/moire unit cell, we consider the spatial features of the STM signal for 14 different many-body correlated states and assess the possibility of Kekule distortion (KD) emerging at the graphene lattice scale. Remarkably, we find that coupling the two opposite graphene valleys in the intervalley-coherent (IVC) TBG insulators does not always result in KD. As an example, we show that the Kramers IVC state and its nonchiral U(4) rotations do not exhibit any KD, while the time-reversal-symmetric IVC state does. Our results, obtained over a large range of energies and model parameters, show that the STM signal and Chern number of a state can be used to uniquely determine the nature of the TBG ground state.
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页数：8
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