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SUMMARY:Strain effect on electronic and structural properties of metal nan
 oislands grown on reconstructed Au(111) - Guido Fratesi\, Materials Scienc
 e Department\, Milano-Bicocca University\, Milan\, Italy
DTSTART:20110413T103000Z
DTEND:20110413T113000Z
UID:TALK30836@talks.cam.ac.uk
CONTACT:Stephen Walley
DESCRIPTION:The growth of various metal elements on the Au(111) surface is
 \ncharacterized by an initial ordered island nucleation at the elbows of\n
 the surface herringbone reconstruction\, where shorter lattice constant\na
 ffects the energetics and electronic properties of the adsorbates.\nHere w
 e focus on Fe and Pd on Au(111)\, investigated by combining\nscanning tunn
 eling microscopy and spectroscopy experiments (STM/STS)\nand density funct
 ional theory simulations (DFT).\n\nA characteristic peak measured in the e
 lectron local density of states\nof Fe/Au(111) at Fermi level indicates th
 e presence of a nondispersive\nminority Fe dz2 state\, while less prominen
 t contributions to the\nLDOS are predicted from the Au(111) surface state 
 upon hybridization\nwith the overlayer Fe states.  The peak energy was mea
 sured to shift\nfrom occupied to unoccupied states as a function of positi
 on within Fe\nislands. We related this effect to the reconstruction-induce
 d local\nFe-Fe bond length variation [1].\n\nThe assignment of atom-size f
 eatures\, observed by STM close to\nherringbone elbows at low Pd coverage\
 , to adsorbed\, substituted\, or\nsubsurface Pd atoms is sometimes dispute
 d in the literature\, and here\naddressed by DFT simulations.  The low act
 ivation barriers computed\nfor the diffusion of adsorbed Pd\, and bias-dep
 endent contrast in\nsimulated tunneling currents following attenuation of 
 the Au(111)\nsp-surface state\, support the interpretation of black spots 
 observed\nin STM as subsurface Pd atoms\, rather than on-surface ones [2].
 \n\n[1] F. Donati\, G. Fratesi\, A. Mairov\, M. Passoni\, C.S. Casari\,\nC
 .E. Bottani\, M.I. Trioni\, and A. Li Bassi\, Phys. Rev. B (2011) in\npres
 s\n\n[2] G. Fratesi\, J. Phys.: Condens. Matter 23\, 015001 (2011)\n\n
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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