气候变化领域集成服务门户(CCPortal): Time-reversal symmetry breaking versus chiral symmetry breaking in twisted bilayer graphene

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DOI	10.1103/PhysRevB.102.081118
	Time-reversal symmetry breaking versus chiral symmetry breaking in twisted bilayer graphene
	González J.; Stauber T.
发表日期	2020
ISSN	24699950
卷号	102 期号:8
英文摘要	By applying a self-consistent Hartree-Fock approximation, we show that the mechanism of dynamical symmetry breaking can account for the insulating phase that develops about the charge neutrality point of twisted bilayer graphene around the magic angle. (i) If the Coulomb interaction is screened by metallic gates, the opening of a gap between the lowest-energy valence and conduction bands proceeds through the breakdown of chiral symmetry at strong coupling. Increasing the dielectric screening, however, we find a critical coupling at which chiral symmetry breaking is suppressed, triggering a very strong signal for time-reversal symmetry breaking with Haldane mass. (ii) If the long-range tail of the Coulomb interaction is not screened, we see the appearance of yet a different dominant pattern at strong coupling, which is characterized by breaking the time-reversal invariance but with opposite flux in the two sublattices of each carbon layer, with the consequent valley symmetry breaking. In this case a gap is also opened in the Dirac cones, but superposed to the splitting of the degeneracy of the low-energy bands at the K points of the moiré Brillouin zone. © 2020 American Physical Society.
scopus关键词	Coulomb interactions; Graphene; Charge neutrality; Critical coupling; Dielectric screening; Dynamical symmetry; Insulating phase; Symmetry-breaking; Time reversal symmetries; Time-reversal invariance; Hartree approximation
来源期刊	Physical Review B
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/176615
作者单位	Instituto de Estructura de la Materia, Csic, Madrid, E-28006, Spain; Materials Science Factory, Instituto de Ciencia de Materiales de Madrid, Csic, Madrid, E-28049, Spain
推荐引用方式 GB/T 7714	González J.,Stauber T.. Time-reversal symmetry breaking versus chiral symmetry breaking in twisted bilayer graphene[J],2020,102(8).
APA	González J.,&Stauber T..(2020).Time-reversal symmetry breaking versus chiral symmetry breaking in twisted bilayer graphene.Physical Review B,102(8).
MLA	González J.,et al."Time-reversal symmetry breaking versus chiral symmetry breaking in twisted bilayer graphene".Physical Review B 102.8(2020).