Properties & Interests Motivations Bismuth nanolines Haiku stripes Interests for 1D Nanolines templating Manganese chains CC BY : Bothered By Bees (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 Si After H exposure Before H exposure B C O O Freshly flashed Si Counts/s Energy Mn chains near Bi nanolines Design by François Bianco under CC-BY-SA licence V = -2.5 V, I = 80 pA V = -2.5 V, I = 200 pA V = +2.5 V, I = 150 pA V = +2.0 V, I = 150 pA Huge aspect ratio (length/width) achievable Stable up to 400°C in UHV Inert in air Stable in real life's lab ! V = -2.2 V, I = 100 pA After 25 min exposure to air 3 nm Bi nanolines 1 nm 1 nm Haiku stripes 1 nm Mn chains Mn deposition 1 nm Si(001) Bi deposition 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 H y d r o g e n at i o n 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 50 nm 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 = -3.0 V, I = 400 pA V = -3.5 V, I = 200 pA V = -2.8 V, I = 200 pA V = -.3.0 V, I = 200 pA 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 = 900 pA Proposed model C-type chains Mn between Si dimers in first layer Fairly good matching between STM simulation (integrated DFT) and experimental data x x z y V = -3.1 V, I = 80 pA Filled state Empty state V = 2.0 V, I = 80 pA 5 nm 5 nm 5 nm 1 nm 1 nm 1 nm Outlook 20 nm Bi nanolines 150 nm V = -2.9 V, I = 100 pA V = -2.0 V, I = 350 pA 1 nm V = -3.3 V, I = 100 pA 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
Poster about atomic nanolines based on silicon only structures
Jul 19, 2015
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Properties & Interests
Motivations
Bismuth nanolines Haiku stripes
Interests for 1D
Nanolines templating
Manganese chains
CC
BY
: B
oth
ere
d B
y B
ees (
Flic
kr)
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
Sim
ula
tio
n
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
Sim
ula
tio
n
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 exposureBefore H exposure
BCO
O
Freshly flashed Si
Co
un
ts/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 Biancounder CC-BY-SA licence
V =
−2.5
V, I
= 8
0 p
A
V =
−
2.5
V, I =
20
0 p
A
V =
+2.5
V, I =
150
pA
V =
+2.0
V, I =
150 p
A
Huge aspect ratio (length/width) achievable
Stable up to 400°C in UHV
Inert in air
Stable in real life's lab !
V =
−
2.2
V, I =
10
0 p
A
After 25 min
exposure to air
3 nm
Bi nanolines
1 nm
1 nm
Haiku stripes
1 nm
Mn chainsM
n d
ep
os
itio
n
1 nm
Si(001)
Bi
de
po
sit
ion
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
Hyd
rogen
ation
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
50 n
m
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 chainsJ. 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
.0 V
, I =
40
0 p
A
V =
−3
.5 V
, I =
20
0 p
A
V =
−2
.8 V
, I =
20
0 p
AV
= −
.3.0
V, I =
20
0 p
A
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
75
7
5
I = 9
00 p
A
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
.1 V
, I =
80 p
A
Filled state Empty state
V =
2.0
V, I =
80 p
A
5 nm
5 nm
5 nm
1 nm 1 nm
1 nm
Ou
tlo
ok
20 nm
Bi nanolines
150 nm
V =
−
2.9
V, I =
100 p
A V
= −
2.0
V,
I =
35
0 p
A
1 nm
V =
−
3.3
V, I =
100 p
A
10 nm
F. Bianco, S. A. Köster, J. H. G. Owen, and Ch. RennerDPMC, MaNEP, University of Geneva
D. R. Bowler
UCL and LCN, London
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