The growth of Fe nanoclusters oN the Ge（001） surface has been studied using low-temperature scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. STM results indicate that Fe nucl...The growth of Fe nanoclusters oN the Ge（001） surface has been studied using low-temperature scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. STM results indicate that Fe nucleates on the Ge（001） surface, forming well-ordered nanoclusters of uniform size. Depending on the preparation conditions, two types of nanoclusters were observed having either four or sixteen Fe atoms within a nanocluster. The results were confirmed by DFT calculations. Annealing the nanoclusters at 420 K leads to the formation of nanorow structures, due to cluster mobility at such temperature. The Fe nanoclusters and nanorow structures formed on the Ge（001） surface show a superparamagnetic behaviour as measured by X-ray magnetic circular dichroism.展开更多
The atomic and electronic structure of graphene synthesized on commercially available cubic-SiC（001）/Si（001） wafers have been studied by low energy electron microscopy （LEEM）, scanning tunneling microscopy （STM...The atomic and electronic structure of graphene synthesized on commercially available cubic-SiC（001）/Si（001） wafers have been studied by low energy electron microscopy （LEEM）, scanning tunneling microscopy （STM）, low energy electron diffraction （LEED）, and angle resolved photoelectron spectroscopy （ARPES）. LEEM and STM data prove the wafer-scale continuity and uniform thickness of the graphene overlayer on SIC（001）. LEEM, STM and ARPES studies reveal that the graphene overlayer on SIC（001） consists of only a few monolayers with physical properties of quasi-freestanding graphene. Atomically resolved STM and micro-LEED data show that the top graphene layer consists of nanometer-sized domains with four different lattice orientations connected through the 〈110〉-directed boundaries. ARPES studies reveal the typical electron spectrum of graphene with the Dirac points close to the Fermi level. Thus, the use of technologically relevant SiC（001）/Si（001） wafers for graphene fabrication repre-sents a realistic way of bridging the gap between the outstanding properties of graphene and their applications.展开更多
基金This work was supported by Science Foundation Ireland （Principal Investigator grant No. 06/IN.1/191 and Research Frontiers Programme grant No. 07/ RFP/MASF185）. The authors wish to thank Trinity College High Performance Cluster, funded by the Higher Education Authority under the Program for Research in Third Level Institutes, for the use of their computing facilities.
文摘The growth of Fe nanoclusters oN the Ge（001） surface has been studied using low-temperature scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. STM results indicate that Fe nucleates on the Ge（001） surface, forming well-ordered nanoclusters of uniform size. Depending on the preparation conditions, two types of nanoclusters were observed having either four or sixteen Fe atoms within a nanocluster. The results were confirmed by DFT calculations. Annealing the nanoclusters at 420 K leads to the formation of nanorow structures, due to cluster mobility at such temperature. The Fe nanoclusters and nanorow structures formed on the Ge（001） surface show a superparamagnetic behaviour as measured by X-ray magnetic circular dichroism.
文摘The atomic and electronic structure of graphene synthesized on commercially available cubic-SiC（001）/Si（001） wafers have been studied by low energy electron microscopy （LEEM）, scanning tunneling microscopy （STM）, low energy electron diffraction （LEED）, and angle resolved photoelectron spectroscopy （ARPES）. LEEM and STM data prove the wafer-scale continuity and uniform thickness of the graphene overlayer on SIC（001）. LEEM, STM and ARPES studies reveal that the graphene overlayer on SIC（001） consists of only a few monolayers with physical properties of quasi-freestanding graphene. Atomically resolved STM and micro-LEED data show that the top graphene layer consists of nanometer-sized domains with four different lattice orientations connected through the 〈110〉-directed boundaries. ARPES studies reveal the typical electron spectrum of graphene with the Dirac points close to the Fermi level. Thus, the use of technologically relevant SiC（001）/Si（001） wafers for graphene fabrication repre-sents a realistic way of bridging the gap between the outstanding properties of graphene and their applications.
