,Electronic structure, Dirac points and Fermi arc surface states in three-dimensional Dirac semimeta

来源 :中国物理B(英文版) | 被引量 : 0次 | 上传用户:shs20000
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The three-dimensional (3D) Dirac semimetals have linearly dispersive 3D Dirac nodes where the conduction band and valence band are connected. They have isolated 3D Dirac nodes in the whole Brillouin zone and can be viewed as a 3D counterpart of graphene. Recent theoretical calculations and experimental results indicate that the 3D Dirac semimetal state can be realized in a simple stoichiometric compound A3Bi (A=Na, K, Rb). Here we report comprehensive high-resolution angle-resolved photoemission (ARPES) measurements on the two cleaved surfaces, (001) and (100), of Na3Bi. On the (001) surface, by comparison with theoretical calculations, we provide a proper assignment of the observed bands, and in particular, pinpoint the band that is responsible for the formation of the three-dimensional Dirac cones. We observe clear evidence of 3D Dirac cones in the three-dimensional momentum space by directly measuring on the kx–ky plane and by varying the photon energy to get access to different out-of-plane kzs. In addition, we reveal new features around the Brillouin zone coers that may be related with surface reconstruction. On the (100) surface, our ARPES measurements over a large momentum space raise an issue on the selection of the basic Brillouin zone in the (100) plane. We directly observe two isolated 3D Dirac nodes on the (100) surface. We observe the signature of the Fermi-arc surface states connecting the two 3D Dirac nodes that extend to a binding energy of~150 meV before merging into the bulk band. Our observations constitute strong evidence on the existence of the Dirac semimetal state in Na3Bi that are consistent with previous theoretical and experimental work. In addition, our results provide new information to clarify on the nature of the band that forms the 3D Dirac cones, on the possible formation of surface reconstruction of the (001) surface, and on the issue of basic Brillouin zone selection for the (100) surface.
其他文献
百合(Lilium)花是世界名花之一,适合用作切花、盆花和园林布景,深受人们的喜爱。具有很高的商业价值和观赏价值,还有食用和药用价值。在我国花卉市场上,无论是芳香醉人的东方(Ori
本研究以茎瘤芥(Brassica juncea Coss.var.tumida Tsen et Lee)作为试验材料,分别以子叶和子叶诱导的愈伤组织为外植体,建立了农杆菌介导的芜菁花叶病毒Hc-Pro基因的转化体系,
We report high-temperature thermodynamics for fcc silver by combining ab initio phonon dynamics to empirical quadratic temperature-dependent term for anharmonic
In the present work,a third form,the so-called HP-BiNbO4 synthesized at high pressure and high temperature is investigated with the in-situ angle-dispersive x-r
以茶树1005品系为研究对象,应用PCR、RACE技术及在线生物信息学分析软件,首次克隆并分析了茶树酯型儿茶素合成前体物质之一GA的生物合成途径中aroB、aroDE基因的全长cDNA序列
We employ ab-initio calculations to analyze the mechanical,electronic,optical and also thermoelectric properties associated with AGeO3 (A =Ca,Sr) compounds.The