scholarly journals Unconventional superconductivity in nearly flat bands in twisted bilayer graphene

2019 ◽  
Vol 99 (12) ◽  
Author(s):  
Bitan Roy ◽  
Vladimir Juričić
Keyword(s):  
Bilayer Graphene ◽  
Unconventional Superconductivity ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

scholarly journals Flat bands in slightly twisted bilayer graphene: Tight-binding calculations

2010 ◽  
Vol 82 (12) ◽  
Author(s):  
E. Suárez Morell ◽  
J. D. Correa ◽  
P. Vargas ◽  
M. Pacheco ◽  
Z. Barticevic
Keyword(s):  
Tight Binding ◽  
Bilayer Graphene ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

scholarly journals Moiré with flat bands is different

2019 ◽  
Vol 50 (3) ◽  
pp. 24-26
Author(s):  
Tero T. Heikkilä ◽  
Timo Hyart
Keyword(s):  
Critical Temperature ◽  
Fermi Surface ◽  
Room Temperature ◽  
Electronic States ◽  
Bilayer Graphene ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

Recent experimental discoveries of superconductivity and other exotic electronic states in twisted bilayer graphene (TBG) call for a reconsideration of our traditional theories of these states, usually based on the assumption of the presence of a Fermi surface. Here we show how such developments may even help us finding mechanisms of increasing the critical temperature of superconductivity towards the room temperature.

scholarly journals Moire Is Different

2021 ◽  
Vol 13 (1) ◽  
pp. 50
Author(s):  
Wenyuan Shi
Keyword(s):  
Electronic Structures ◽  
Tight Binding ◽  
Physical Property ◽  
Large Change ◽  
Bilayer Graphene ◽  
Dirac Fermion ◽  
Dirac Fermions ◽  
Graphene Layers ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

Graphene, as the thinnest material ever found, exhibits unconventionally relativistic behaviour of Dirac fermions. However, unusual phenomena (such as superconductivity) arise when stacking two graphene layers and twisting the bilayer graphene. The relativistic Dirac fermion in graphene has been widely studied and understood, but the large change observed in twisted bilayer graphene (TBG) is intriguing and still unclear because only van der Waals force (vdW) interlayer interaction is added from graphene to TBG and such a very weak interaction is expected to play a negligible role. To understand such dramatic variation, we studied the electronic structures of monolayer, bilayer and twisted bilayer graphene. Twisted bilayer graphene creates different moiré patterns when turned at different angles. We proposed tight-binding and effective continuum models and thereby drafted a computer code to calculate their electronic structures. Our calculated results show that the electronic structure of twisted bilayer graphene changes significantly even by a tiny twist. When bilayer graphene is twisted at special “magic angles”, flat bands appear. We examined how these flat bands are created, their properties and the relevance to some unconventional physical property such as superconductivity. We conclude that in the nanoscopic scale, similar looking atomic structures can create vastly different electronic structures. Like how P. W. Anderson stated that similar looking fields in science can have differences in his article “More is Different”, similar moiré patterns in twisted bilayer graphene can produce different electronic structures.

scholarly journals Evidence for unconventional superconductivity in twisted bilayer graphene

Nature ◽  
2021 ◽  
Author(s):  
Myungchul Oh ◽  
Kevin P. Nuckolls ◽  
Dillon Wong ◽  
Ryan L. Lee ◽  
Xiaomeng Liu ◽  
...  
Keyword(s):  
Bilayer Graphene ◽  
Unconventional Superconductivity ◽  
Twisted Bilayer Graphene

Full-Spectrum Thermal Analysis in Twisted Bilayer Graphene

2021 ◽  
Author(s):  
Wenxiang Liu ◽  
Yongqiang Wu ◽  
Yang Hong ◽  
Bo Hou ◽  
Jingchao Zhang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Bilayer Graphene ◽  
Magic Angle ◽  
Unconventional Superconductivity ◽  
Full Spectrum ◽  
Twisted Bilayer Graphene ◽  
Twisting Angle

It was recently reported that a magic angle, i.e. 1.1º, exists in twisted bilayer graphene which could lead to intrinsic unconventional superconductivity. Variations of the twisting angle between different graphene...

scholarly journals Electrically Tunable Flat Bands and Magnetism in Twisted Bilayer Graphene

2019 ◽  
Vol 123 (9) ◽  
Author(s):  
T. M. R. Wolf ◽  
J. L. Lado ◽  
G. Blatter ◽  
O. Zilberberg
Keyword(s):  
Bilayer Graphene ◽  
Flat Bands ◽  
Twisted Bilayer Graphene

scholarly journals Harmonic fingerprint of unconventional superconductivity in twisted bilayer graphene

2020 ◽  
Vol 101 (13) ◽  
Author(s):  
Xianxin Wu ◽  
Werner Hanke ◽  
Mario Fink ◽  
Michael Klett ◽  
Ronny Thomale
Keyword(s):  
Bilayer Graphene ◽  
Unconventional Superconductivity ◽  
Twisted Bilayer Graphene

scholarly journals Designing spin-textured flat bands in twisted graphene multilayers via helimagnet encapsulation

2D Materials ◽  
2022 ◽  
Author(s):  
Guangze Chen ◽  
Maryam Khosravian ◽  
Jose Lado ◽  
Aline Ramires
Keyword(s):  
Helical Structure ◽  
Bilayer Graphene ◽  
Flat Band ◽  
Two Dimensional ◽  
Local Exchange ◽  
Flat Bands ◽  
Starting Point ◽  
Twisted Bilayer Graphene ◽  
Spin Texture ◽  
Twisted Graphene

Abstract Twisted graphene multilayers provide tunable platforms to engineer flat bands and exploit the associated strongly correlated physics. The two-dimensional nature of these systems makes them suitable for encapsulation by materials that break specific symmetries. In this context, recently discovered two-dimensional helimagnets, such as the multiferroic monolayer NiI2, are specially appealing for breaking time-reversal and inversion symmetries due to their nontrivial spin textures. Here we show that this spin texture can be imprinted on the electronic structure of twisted bilayer graphene by proximity effect. We discuss the dependence of the imprinted spin texture on the wave-vector of the helical structure, and on the strength of the effective local exchange field. Based on these results we discuss the nature of the superconducting instabilities that can take place in helimagnet encapsulated twisted bilayer graphene. Our results put forward helimagnetic encapsulation as a powerful way of designing spin-textured flat band systems, providing a starting point to engineer a new family of correlated moire states.

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