Poster about atomic nanolines based on silicon only structures
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Achievement of fabricating and understanding nanostructure will able us to build new electronic component. This work show our analysis of one structure we found in Silicon based on the Bismuth Nanolines.
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Poster about atomic nanolines based on silicon only structures
- 1. Properties & Interests Motivations Bismuth nanolines Haiku stripes Interests for 1D Nanolines templating Manganese chains CCBY:BotheredByBees(Flickr) Explore 1D experimentally Probe the Tomanaga-Luttinger liquid theory More versatile than systems on vicinal surfaces Interconnects for novel electronics Why 1D chains on Si(001)? Implement the infinite length limit condition addressed by theory 4 Si dimers wide, 1.54 nm ⊥ Si dimers Straight, no kinks Nearly defect free Length limited by defects and terraces Tunable line density Self-assembled No vicinal surface Independent of step edges Gapped substrate Industrially relevant surface Filled state 1 nm Low current 1 nm High current +2.5 V +2.0 V + 2.0 V 1 nm + 2.5 V y x y z 1D delocalized state close to the Si band gap Purely electronic effect Data Simulation Data Reproduce the 1D central state… … and predict it as delocalized along the nanoline Empty state Charge densities simulations Electronic effects : both central atoms are rised at high current Very good matching between STM simulation (integrated DFT) and experimental data Run along the nanolines Does not correspond to any atom position in the structure 1 nm Simulation Perfect 1D electronic model system ? Data Simulation Data Simulation Synthesis Haiku stripes form by exposing Bi nanolines to hydrogen: Bi dimers are stripped by H, exact mechanism not yet understood Si reconstruction (Haiku structure) below the Bi nanolines Composed of 5- and 7- fold rings of Si extending 5 layers below the surface No trace of contaminations after hydrogenation in XPS XPS Bi Bi Bi Si SiAfter H exposure Before H exposure B CO O Freshly flashed Si Counts/s Energy Mn chains near Bi nanolines Drawn freely with FONDS NATIONAL SUISSE SCHWEIZERISCHE NATIONALFONDS FONDO NAZIONALE SVIZZERO SWISS NATIONAL SCIENCE FOUNDATION FN NFS Design by François Bianco under CC-BY-SA licence V=−2.5V,I=80pA V=−2.5V,I=200pA V=+2.5V,I=150pA V=+2.0V,I=150pA Huge aspect ratio (length/width) achievable Stable up to 400°C in UHV Inert in air Stable in real life's lab ! V=−2.2V,I=100pA After 25 min exposure to air 3 nm Bi nanolines 1 nm 1 nm Haiku stripes 1 nm Mn chainsMndeposition 1 nm Si(001) Bideposition Haiku structure Sena, Bowler, J. Phys.: Cond. Matt. 23 (2011) 305003 Liu et al. Surf. Sci. 602 (2008) 986 Interesting magnetic structure predicted by spin polarized DFT Unusual zig-zag chain structure Structure still under investigation together with DFT modelling Bi nanolines promote growth of long Mn chains Up to 40 atoms chains (self-assembled) Double chain of Bi dimers Bias dependant contrast in filled state reproduced by STM simulation Bi nanolines grow on Si(001) at 570°C Strained Si dimers -2.5 V -2.3 V -3.0 V Strained Si dimers -2.5 V -2.3 V -3.0 V Hydrogenati on Mn chains forms between Bi nanolines Perfect 1D spin chain model system ? Spin densities simulations Model z x Haiku stripes Mn chains are good candidate for 1D spin system Look for metallic properties... .... and contacting for transport measurements Optical measurements 50nm Streched 2× vertically V = −2.5 V, I = 180 pA 1.3 µm long Promising 1D templates for atom chain assembly Hydrogen covered Haiku structure, no Bi Au, Ag atomic chains J. Phys. Cond. Matt. 19, 226213 (2007) Mat. Sci. and Eng. 140, 160 (2007) Fe interstitial atomic chains Nearby Mn atomic chains Appl. Phys. Lett. 89, 09315 (2006) Appl. Surf. Sci. 254, 96 (2007) Surf. Sci, 602, 986 (2008) Deposition flux Potential wells Diffusion constants Surface energy Peirels instabilities Spinon and holons Possible metalic chains on Si(001) and Bi-nanolines : V=−3.0V,I=400pA V=−3.5V,I=200pA V=−2.8V,I=200pAV=−.3.0V,I=200pA F. Bianco, Phys. Rev. B, 84, 035328 (2011)J. Owen, et al. J. Mater. Sci. 41, 4568 (2006) S. A. Köster, in prep. (2012) old pond . . . a frog leaps in water’s sound 古池や 蛙飛込む 水の音 5 7 5 7 5 I=900pA Proposed model C-type chains Mn between Si dimers in first layer Fairly good matching between STM simulation (integrated DFT) and experimental datax x z y V=−3.1V,I=80pA Filled state Empty state V=2.0V,I=80pA 5 nm 5 nm 5 nm 1 nm 1 nm 1 nm Outlook 20 nm Bi nanolines 150 nm V=−2.9V,I=100pA V=−2.0V,I=350pA 1 nm V=−3.3V,I=100pA 10 nm F. Bianco, S. A. Köster, J. H. G. Owen, and Ch. Renner DPMC, MaNEP, University of Geneva D. R. Bowler UCL and LCN, London