Angle-Dependent van Hove Singularities in a Slightly Twisted Graphene   Bilayer

doi:10.1103/PhysRevLett.109.126801

CORC > 北京大学 > 化学与分子工程学院

	Angle-Dependent van Hove Singularities in a Slightly Twisted Graphene Bilayer
	Yan, Wei ; Liu, Mengxi ; Dou, Rui-Fen ; Meng, Lan ; Feng, Lei ; Chu, Zhao-Dong ; Zhang, Yanfeng ; Liu, Zhongfan ; Nie, Jia-Cai ; He, Lin
刊名	物理评论快报
	2012
关键词	SCANNING-TUNNELING-MICROSCOPY ELECTRONIC-PROPERTIES ATOMIC-RESOLUTION DIRAC FERMIONS BERRYS PHASE GRAPHITE HONEYCOMB STM TEMPERATURE IMAGES
DOI	10.1103/PhysRevLett.109.126801
英文摘要	Recent studies show that two low-energy van Hove singularities (VHSs) seen as two pronounced peaks in the density of states could be induced in a twisted graphene bilayer. Here, we report angle-dependent VHSs of a slightly twisted graphene bilayer studied by scanning tunneling microscopy and spectroscopy. We show that energy difference of the two VHSs follows Delta E-vhs similar to (h) over bar nu(F)Delta K between 1.0 degrees and 3.0 degrees [here nu(F) similar to 1.1 x 10(6) m/s is the Fermi velocity of monolayer graphene, and Delta K = 2K sin(theta/2) is the shift between the corresponding Dirac points of the twisted graphene bilayer]. This result indicates that the rotation angle between graphene sheets does not result in a significant reduction of the Fermi velocity, which quite differs from that predicted by band structure calculations. However, around a twisted angle theta similar to 1.3 degrees, the observed Delta E-vhs similar to 0.11 eV is much smaller than the expected value (h) over bar nu(F)Delta K similar to 0.28 eV at 1.3 degrees. The origin of the reduction of Delta E-vhs at 1.3 degrees is discussed.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000308877000003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; Physics, Multidisciplinary; SCI(E); EI; 60; ARTICLE; 12; 109
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/392805]
专题	化学与分子工程学院工学院
推荐引用方式 GB/T 7714	Yan, Wei,Liu, Mengxi,Dou, Rui-Fen,et al. Angle-Dependent van Hove Singularities in a Slightly Twisted Graphene Bilayer[J]. 物理评论快报,2012.
APA	Yan, Wei.,Liu, Mengxi.,Dou, Rui-Fen.,Meng, Lan.,Feng, Lei.,...&He, Lin.(2012).Angle-Dependent van Hove Singularities in a Slightly Twisted Graphene Bilayer.物理评论快报.
MLA	Yan, Wei,et al."Angle-Dependent van Hove Singularities in a Slightly Twisted Graphene Bilayer".物理评论快报 (2012).