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.

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