Multiple unpinned Dirac points in group-Va single-layers with phosphorene structure  

作　　者：Yunhao Lu Di Zhou Guoqing Chang Shan Guan Weiguang Chen Yinzhu Jiang Jianzhong Jiang Xue-sen Wang Shengyuan A Yang Yuan Ping Feng Yoshiyuki Kawazoe Hsin Lin 

机构地区：[1]School of Materials Science and Engineering,Zhejiang University,Hangzhou,China [2]State Key Laboratory of Silicon Materials,Zhejiang University,Hangzhou,China [3]Centre for Advanced 2D Materials and Graphene Research Centre,National University of Singapore,Singapore,Singapore [4]Department of Physics,National University of Singapore,Singapore,Singapore [5]Research Laboratory for Quantum Materials,Singapore University of Technology and Design,Singapore,Singapore [6]College of Physics and Electronic Engineering,Zhengzhou Normal University,Zhengzhou,China [7]New Industry Creation Hatchery Center,Tohuku University,Sendai,Japan [8]Institute of Thermophysics,Siberian Branch of Russian Academy of Sciences,Novosibirsk,Russia

出　　处：《npj Computational Materials》2016年第1期142-148,共7页计算材料学（英文）

基　　金：supported by NSFC(Grant No.11374009,61574123 and 21373184);the National Key Basic Research Program of China(2012CB825700);SUTD-SRG-EPD2013062;Singapore MOE Academic Research Fund Tier 1(SUTD-T1-2015004);A*STAR SERC 122-PSF-0017 and AcRF R-144-000-310-112;support by Singapore National Research Foundation under NRF Award No.NRF-NRFF2013-03;Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase);support from SR16000 supercomputing resources of the Center for Computational Materials Science,Tohoku University.

摘　　要：Emergent Dirac fermion states underlie many intriguing properties of graphene,and the search for them constitutes one strong motivation to explore two-dimensional(2D)allotropes of other elements.Phosphorene,the ultrathin layers of black phosphorous,has been a subject of intense investigations recently,and it was found that other group-Va elements could also form 2D layers with similar puckered lattice structure.Here,by a close examination of their electronic band structure evolution,we discover two types of Dirac fermion states emerging in the low-energy spectrum.One pair of(type-I)Dirac points is sitting on high-symmetry lines,while two pairs of(type-II)Dirac points are located at generic k-points,with different anisotropic dispersions determined by the reduced symmetries at their locations.Such fully-unpinned(type-II)2D Dirac points are discovered for the first time.In the absence of spin-orbit coupling(SOC),we find that each Dirac node is protected by the sublattice symmetry from gap opening,which is in turn ensured by any one of three point group symmetries.The SOC generally gaps the Dirac nodes,and for the type-I case,this drives the system into a quantum spin Hall insulator phase.We suggest possible ways to realise the unpinned Dirac points in strained phosphorene.

关 键 词：STRUCTURE SPECTRUM DIRAC 

分 类 号：O41[理学—理论物理]