Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
Doping metallic chemically active nanocontacts:
Pt H2Auand in a environment.
Yamila.García
Applied Physics Department, Alicante University,Spain
Is the interpretation of current experiments in molecular electronics beyond the reach of standard (LDA)
first-principles-transport-calculations?
2. H2 act as a local dopant on Pt and Au nanocontacts:
Our numerical results & experimental information.
1. ≠Ab-initio DFT:
Remarks & Outline:
Single Molecule Devices:
VI
∂∂
=G
( ) [ ]−+= GΓGΓ RLTrET
0=V
towards an electronic characterization
( )EThe22
= : Landauer Formalism
FE
ab-initio calculations
2- Atomic configurations3- Model for the electrodes
Quantum Chemistry tools for 4- Basis sets
5- The method: HF,DFT,…,FCI
1- Experimental set up
0=T
Left electrode Right electrode
Bulk + + Bulk Nanojunction
Energetic alignment at the contact
Left electrode Right electrodeBulk + + Bulk Nanojunction
HOMO
LUMO
GAPFermi level Fermi level
atomos/molecules
GAP
Energetic alignment at the contact
FCI
LDA
GGA
MGGA
+ =Hybrid Methods
hLDA
hGGA
hMGGA
B3LYP
3.93.8Ni
3.83.6MnO
7.37.8MgO
3.23.4ZnO
1.51.4GaAs
5.85.5Diamond
3.83.5Si
B3LYPExp.Material
BAND GAPS [eV]
J.Muscat,A.Wander,N.M.Harrison, Chem.Phys.Lett,342 (2001) 397-401
Q u
a l
i t y
HF
Wave Function Density Functional
For a numerical solution of the many-body–electronic problem
GAP GAP GAP
DOS [arb.units] DOS [arb.units]
[E-EFerm
i ] eVCO
ND
UCT
ANCE
[2 e
2/h
]
[E-EFermi] eV
an attempt to explain the evolution of spectral densities
LDA or B3LYP?That is the question.
R.H.M. Smit,Y.Noat,C.Untiedt,N.D.Lang,M.van Hemert,J.M.vanRuitenbeek, Nature 419, 906 (2002)
0.
0.8
0.6
0.4
0.2
Pt/H2
Pt
0 1 2 3 4 5
Num
ber o
f cou
nts
Conductance (2e2/h)
The smallest molecular bridge?
Zone d(PtPt)[nm]
G[2e2/h]
1 27 1.0
2 50 0.2
1 2
~ ~
SINGLE Molecule Chemistry
Doping:H2 charging a Pt nanocontact.
[E-EFermi] eV
CO
ND
UCT
ANCE
[2 e
2/h
]
d-orbitals contribution at the contact
Pt contact
Pt doped contact
DO
S [a
rb.u
nits
]
0 0.3-0.3[E-EFermi] eV
• Conductance
• Directionality
Remarks:
Sz.Czonka, A.Halbritter,G.Mihaly, Cond-Mat/0502421
Conductance (2e2/h)
Num
ber o
f cou
nts
1 2 3
1 2 3
Au
Au/H2
The smallest molecule vs. the noblest metal
3
Zone d(AuAu)[nm]
G[2e2/h]
1 24 1.0
2 28 0.2-0.5
3 36 0
~ ~
SINGLE Molecule Chemistry
1 2
Doping:H2 disturb a Au nanocontact.
CO
ND
UCT
ANCE
[2 e
2/h
]
[E-EFermi] eV
s-orbitals contribution in the chain
Au chain
Au doped chain
DO
S [a
rb.u
nits
]
[E-EFermi] eV-0.3 0.30
Remarks:
• Conductance
• Directionality
Future Work
• Inelastic scattering events• Large size molecules• Finite bias• Finite temperature• …..
In collaboration with:
J.J. Palacios
E. Louis
E. SanFabián
A. J. Pérez-Jiménez
J. A. Vergés
Applied Physics Department,Alicante University,Spain
Applied Physics Department,Alicante University,Spain
Physical-Chemistry Department,Alicante University,Spain
Physical-Chemistry Department,Alicante University,Spain
Materials Science Institute of Madrid, Spain
ADEU BARCELONA