This paper reports that the growth of RuO2（110） thin layer growth on Ru（0001） has been investigated by means of scanning tunnelling microscope （STM）. The STM images showed a domain structure with three rotationa...This paper reports that the growth of RuO2（110） thin layer growth on Ru（0001） has been investigated by means of scanning tunnelling microscope （STM）. The STM images showed a domain structure with three rotational domains of RuO2（110） rotated by an angle of 120°. The as-grown RuO2（110） thin layer is expanded from the bulk-truncated RuO2（110） due to the large mismatch between RuO2（110） and the Ru（0001） substrate. The results also indicate that growth of RuO2（110） thin layer on the Ru（0001） substrate by oxidation tends first to formation of the Ru-O （oxygen） chains in the [001] direction of RuO2 （110）.展开更多
Transition metal ditellurides(TMTDs)have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin texture.Controlled growth of high-quality and large-scale monolayer TMTDs wit...Transition metal ditellurides(TMTDs)have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin texture.Controlled growth of high-quality and large-scale monolayer TMTDs with preferred crystal phases is crucial for their applications.Here,we demonstrate the epitaxial growth of 1T'-MoTe_(2) on Au(111)and graphitized silicon carbide(Gr/SiC)by molecular beam epitaxy(MBE).We investigate the morphology of the grown1T'-MoTe_(2) at the atomic level by scanning tunnelling microscopy(STM)and reveal the corresponding microscopic growth mechanism.It is found that the unique ordered Te structures preferentially deposited on Au(111)regulate the growth of monolayer single crystal 1T'-MoTe_(2),while the Mo clusters were preferentially deposited on the Gr/SiC substrate,which impedes the ordered growth of monolayer MoTe_(2).We confirm that the size of single crystal 1T'-MoTe_(2) grown on Au(111)is nearly two orders of magnitude larger than that on Gr/SiC.By scanning tunnelling spectroscopy(STS),we observe that the STS spectrum of the monolayer 1T'-MoTe_(2) nano-island at the edge is different from that at the interior,which exhibits enhanced conductivity.展开更多
Group-V elemental nanofilms were predicted to exhibit interesting physical properties such as nontrivial topological properties due to their strong spin-orbit coupling,the quantum confinement,and surface effect.It was...Group-V elemental nanofilms were predicted to exhibit interesting physical properties such as nontrivial topological properties due to their strong spin-orbit coupling,the quantum confinement,and surface effect.It was reported that the ultrathin Sb nanofilms can undergo a series of topological transitions as a function of the film thickness h:from a topological semimetal(h>7.8 nm)to a topological insulator(7.8 nm>h>2.7 nm),then a quantum spin Hall(QSH)phase(2.7 nm>h>1.0 nm)and a topological trivial semiconductor(h<1.0 nm).Here,we report a comprehensive investigation on the epitaxial growth of Sb nanofilms on highly oriented pyrolytic graphite(HOPG)substrate and the controllable thermal desorption to achieve their specific thickness.The morphology,thickness,atomic structure,and thermal-strain effect of the Sb nanofilms were characterized by a combination study of scanning electron microscopy(SEM),atomic force microscopy(AFM),and scanning tunneling microscopy(STM).The realization of Sb nanofilms with specific thickness paves the way for the further exploring their thickness-dependent topological phase transitions and exotic physical properties.展开更多
Direct coupling or transformation of inert alkanes based on the selective C-H activation is of great importance for both chemistry and chemical engineering.Here,we report the coupling of polyenes that are transformed ...Direct coupling or transformation of inert alkanes based on the selective C-H activation is of great importance for both chemistry and chemical engineering.Here,we report the coupling of polyenes that are transformed from n-dotriacontane(n-C_(22)H_(66))through on-surface cascade dehydrogenation on Cu(110)surface,leading to the formation of polyacetylene(PA).Three distinct linkages have been resolved by scanning tunneling microscope(STM)and noncontact atomic force microscope(nc-AFM).Apart from the α-type linkage which is the stemless coupling of the terminal C-C double bond in trans-configuration,β-and γ-type linkages appear as knots or defects which are,in fact,the C-C couplings in cis-configurations.Interestingly,the“defects”can be effectively suppressed by adjusting the surface coverage,thus making it of general interest for uniform structure modulation.展开更多
Functionalized two-dimensional(2D)materials play an important role in both fundamental sciences and practical applications.The construction and precise control of patterns at the atomic-scale are necessary for selecti...Functionalized two-dimensional(2D)materials play an important role in both fundamental sciences and practical applications.The construction and precise control of patterns at the atomic-scale are necessary for selective and multiple functionalization.Here we report the fabrication of monolayer pentasilver diselenide(Ag_(5)Se_(2)),a new type of intrinsically patterned 2D material,by direct selenization of a Ag(111)surface.The atomic arrangement is determined by a combination of scanning tunneling microscopy(STM),low-energy electron diffraction(LEED),and density-functional-theory(DFT)calculations.Large-scale STM images exhibit a quasi-periodic pattern of stoichiometric triangular domains with a side length of~15 nm and apical offsets.The boundaries between triangular domains are sub-stoichiometric.Deposition of different molecules on the patterned Ag_(5)Se_(2) exhibits selective adsorption behavior.Pentacene molecules preferentially adsorb on the boundaries,while tetracyanoquinodimethane(TCNQ)molecules adsorb both on the boundaries and the triangular domains.By co-depositing pentacene and TCNQ molecules,we successfully construct molecular corrals with pentacene on the boundaries encircling TCNQ molecules on the triangular domains.The realization of epitaxial large-scale and high-quality,monolayer Ag_(5)Se_(2) extends the family of intrinsically patterned 2D materials and provides a paradigm for dual functionalization of 2D materials.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10274072）, and the Specialized Research Fund for the Doctoral Program of Higher Education of China （Grant No 20030335017）.
文摘This paper reports that the growth of RuO2（110） thin layer growth on Ru（0001） has been investigated by means of scanning tunnelling microscope （STM）. The STM images showed a domain structure with three rotational domains of RuO2（110） rotated by an angle of 120°. The as-grown RuO2（110） thin layer is expanded from the bulk-truncated RuO2（110） due to the large mismatch between RuO2（110） and the Ru（0001） substrate. The results also indicate that growth of RuO2（110） thin layer on the Ru（0001） substrate by oxidation tends first to formation of the Ru-O （oxygen） chains in the [001] direction of RuO2 （110）.
基金Project supported by the National Key R&D Program of China (Grant No.2022YFA1204302)the National Natural Science Foundation of China (Grant Nos.52022029,52221001,92263107,U23A20570,62090035,U19A2090,and 12174098)+1 种基金the Hunan Provincial Natural Science Foundation of China (Grant Nos.2022JJ30142 and 2019XK2001)in part supported by the State Key Laboratory of Powder Metallurgy,Central South University。
文摘Transition metal ditellurides(TMTDs)have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin texture.Controlled growth of high-quality and large-scale monolayer TMTDs with preferred crystal phases is crucial for their applications.Here,we demonstrate the epitaxial growth of 1T'-MoTe_(2) on Au(111)and graphitized silicon carbide(Gr/SiC)by molecular beam epitaxy(MBE).We investigate the morphology of the grown1T'-MoTe_(2) at the atomic level by scanning tunnelling microscopy(STM)and reveal the corresponding microscopic growth mechanism.It is found that the unique ordered Te structures preferentially deposited on Au(111)regulate the growth of monolayer single crystal 1T'-MoTe_(2),while the Mo clusters were preferentially deposited on the Gr/SiC substrate,which impedes the ordered growth of monolayer MoTe_(2).We confirm that the size of single crystal 1T'-MoTe_(2) grown on Au(111)is nearly two orders of magnitude larger than that on Gr/SiC.By scanning tunnelling spectroscopy(STS),we observe that the STS spectrum of the monolayer 1T'-MoTe_(2) nano-island at the edge is different from that at the interior,which exhibits enhanced conductivity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21622304,61674045,11604063,and 61911540074)the National Key Research and Development Program of China(Grant No.2016YFA0200700)+2 种基金the Strategic Priority Research Program and Key Research Program of Frontier Sciences and Instrument Developing Project(Chinese Academy of Sciences,CAS)(Grant Nos.XDB30000000,QYZDB-SSW-SYS031,and YZ201418)Z.H.Cheng was supported by Distinguished Technical Talents Project and Youth Innovation Promotion Association CAS,the Fundamental Research Funds for the Central Universities,Chinathe Research Funds of Renmin University of China(Grant No.18XNLG01).
文摘Group-V elemental nanofilms were predicted to exhibit interesting physical properties such as nontrivial topological properties due to their strong spin-orbit coupling,the quantum confinement,and surface effect.It was reported that the ultrathin Sb nanofilms can undergo a series of topological transitions as a function of the film thickness h:from a topological semimetal(h>7.8 nm)to a topological insulator(7.8 nm>h>2.7 nm),then a quantum spin Hall(QSH)phase(2.7 nm>h>1.0 nm)and a topological trivial semiconductor(h<1.0 nm).Here,we report a comprehensive investigation on the epitaxial growth of Sb nanofilms on highly oriented pyrolytic graphite(HOPG)substrate and the controllable thermal desorption to achieve their specific thickness.The morphology,thickness,atomic structure,and thermal-strain effect of the Sb nanofilms were characterized by a combination study of scanning electron microscopy(SEM),atomic force microscopy(AFM),and scanning tunneling microscopy(STM).The realization of Sb nanofilms with specific thickness paves the way for the further exploring their thickness-dependent topological phase transitions and exotic physical properties.
基金financially supported by the National Natural Science Foundation of China(21790053,and 51821002)the Ministry of Science and Technology(2017YFA0205002)+1 种基金the Collaborative Innovation Center of Suzhou Nano Science&Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the 111 project。
文摘Direct coupling or transformation of inert alkanes based on the selective C-H activation is of great importance for both chemistry and chemical engineering.Here,we report the coupling of polyenes that are transformed from n-dotriacontane(n-C_(22)H_(66))through on-surface cascade dehydrogenation on Cu(110)surface,leading to the formation of polyacetylene(PA).Three distinct linkages have been resolved by scanning tunneling microscope(STM)and noncontact atomic force microscope(nc-AFM).Apart from the α-type linkage which is the stemless coupling of the terminal C-C double bond in trans-configuration,β-and γ-type linkages appear as knots or defects which are,in fact,the C-C couplings in cis-configurations.Interestingly,the“defects”can be effectively suppressed by adjusting the surface coverage,thus making it of general interest for uniform structure modulation.
基金supported by the National Natural Science Foundation of China(No.21972129)the Ministry of Science and Technology of China(2016YFA0200603)Anhui Initiative in Quantum Information Technologies(AHY090000)。
基金supported by the financial support from the National Key R&D Program of China(Nos.2018YFA0305800 and 2019YFA0308500)National Natural Science Foundation of China(Nos.61901200,61925111,61888102,and 21661132006)+4 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB30000000 and XDB28000000)the International Partnership Program of Chinese Academy of Sciences(No.112111KYSB20160061)the KC Wong Education Foundation,the Yunnan Fundamental Research Projects(Nos.2019FD041,202201AT070078,and 202101AW070010)the China Postdoctoral Science Foundationsupported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Science and Engineering Division grant No.DE-FG-02-09ER46554 and by the McMinn endowment.
文摘Functionalized two-dimensional(2D)materials play an important role in both fundamental sciences and practical applications.The construction and precise control of patterns at the atomic-scale are necessary for selective and multiple functionalization.Here we report the fabrication of monolayer pentasilver diselenide(Ag_(5)Se_(2)),a new type of intrinsically patterned 2D material,by direct selenization of a Ag(111)surface.The atomic arrangement is determined by a combination of scanning tunneling microscopy(STM),low-energy electron diffraction(LEED),and density-functional-theory(DFT)calculations.Large-scale STM images exhibit a quasi-periodic pattern of stoichiometric triangular domains with a side length of~15 nm and apical offsets.The boundaries between triangular domains are sub-stoichiometric.Deposition of different molecules on the patterned Ag_(5)Se_(2) exhibits selective adsorption behavior.Pentacene molecules preferentially adsorb on the boundaries,while tetracyanoquinodimethane(TCNQ)molecules adsorb both on the boundaries and the triangular domains.By co-depositing pentacene and TCNQ molecules,we successfully construct molecular corrals with pentacene on the boundaries encircling TCNQ molecules on the triangular domains.The realization of epitaxial large-scale and high-quality,monolayer Ag_(5)Se_(2) extends the family of intrinsically patterned 2D materials and provides a paradigm for dual functionalization of 2D materials.
